Low-e matchable coated articles having absorber film and corresponding methods

ABSTRACT

A low-E coating has good color stability (a low ΔE* value) upon heat treatment (HT). Thermal stability may be improved by the provision of an as-deposited crystalline or substantially crystalline layer of or including zinc oxide, doped with at least one dopant (e.g., Sn), immediately under an infrared (IR) reflecting layer of or including silver; and/or by the provision of at least one dielectric layer of or including an oxide of zirconium. These have the effect of significantly improving the coating&#39;s thermal stability (i.e., lowering the ΔE* value). An absorber film may be designed to adjust visible transmission and provide desirable coloration, while maintaining durability and/or thermal stability. The dielectric layer (e.g., of or including an oxide of Zr) may be sputter-deposited so as to have a monoclinic phase in order to improve thermal stability.

This application is a Continuation-in-Part (CIP) of U.S. applicationSer. No. 16/355,966, filed Mar. 18, 2019, which is aContinuation-in-Part (CIP) of U.S. application Ser. No. 16/220,037,filed Dec. 14, 2018, which is a Continuation-in-Part (CIP) of U.S.application Ser. No. 16/035,810, filed Jul. 16, 2018 (now U.S. Pat. No.10,031,215), the disclosures of which are all hereby incorporated hereinby reference in their entireties.

This invention relates to low-E coated articles that have approximatelythe same color characteristics as viewed by the naked eye both beforeand after heat treatment (e.g., thermal tempering), and correspondingmethods. Such articles may in certain example embodiments combine two ormore of: (1) desirable visible transmission characteristics, (2) gooddurability before and/or after heat treatment, (3) a low ΔE* value whichis indicative of color stability upon heat treatment (HT), and/or (4) anabsorber film designed to adjust visible transmission and providedesirable coloration for the coated article, while maintainingdurability and/or thermal stability. Such coated articles may be usedmonolithically for windows, in insulating glass (IG) window units,laminated window units, vehicle windshields, and/or other vehicle orarchitectural or residential window applications.

BACKGROUND OF THE INVENTION

There is a need for substantial matchability (before heat treatment vs.after heat treatment). Glass substrates are often produced in largequantities and cut to size in order to fulfill the needs of a particularsituation such as a new multi-window office building, vehicle windowneeds, etc. It is often desirable in such applications that some of thewindows and/or doors be heat treated (i.e., tempered, heat strengthenedor heat-bent) while others need not be. Office buildings often employ IGunits and/or laminates for safety and/or thermal control. It isdesirable that the units and/or laminates which are heat treated (HT)substantially match their non-heat treated counterparts (e.g., withregard to color, reflectance, transmission, and/or the like, at least onthe side to be viewed from outside the building) for architecturaland/or aesthetic purposes.

Commonly owned U.S. Pat. No. 5,688,585 discloses a solar control coatedarticle including: glass/Si₃N₄/NiCr/Si₃N₄. One object of the '585 patentis to provide a sputter coated layer system that after heat treatment(HT) is matchable colorwise with its non-heat treated counterpart. Whilethe coating systems of the '585 patent are excellent for their intendedpurposes, they suffer from certain disadvantages. In particular, theytend to have rather high emissivity and/or sheet resistance values(e.g., because no silver (Ag) layer is disclosed in the '585 patent).

It has in the prior art been possible to achieve matchability in systemsother than those of the aforesaid '585 patent, between two differentlayer systems, one of which is heat treated and the other is not. Thenecessity of developing and using two different layer systems to achievematchability creates additional manufacturing expense and inventoryneeds which are undesirable.

U.S. Pat. Nos. 6,014,872 and 5,800,933 (see Example B) disclose a heattreatable low-E layer system including:glass/TiO₂/Si₃N₄/NiCr/Ag/NiCr/Si₃N₄. Unfortunately, when heat treatedthis low-E layer system is not approximately matchable colorwise withits non-heat treated counterpart (as viewed from the glass side). Thisis because this low-E layer system has a ΔE* (glass side) value greaterthan 4.1 (i.e., for Example B, Δa*_(G) is 1.49, Δb*_(G) is 3.81, and ΔL*(glass side) is not measured; using Equation (1) below then ΔE* on theglass side must necessarily be greater than 4.1 and is probably muchhigher than that).

U.S. Pat. No. 5,563,734 discloses a low-E coating system including:substrate/TiO₂/NiCrN_(x)/Ag/NiCrN_(x)/Si₃N₄. Unfortunately, it has beenfound that when high Nitrogen (N) flow rates are used when forming theNiCrN_(x) layers (see the high N flow rate of 143 sccm in Table 1 of the'734 patent; translating into about 22 sccm/kW), the resulting coatedarticles are not color stable with heat treatment (i.e., they tend tohave high ΔE* (glass side) values greater than 6.0). In other words, ifsubjected to HT, the '734 patent low-E layer system would not beapproximately matchable colorwise with its non-heat treated counterpart(as viewed from the glass side).

Moreover, it is sometimes desirable for a coated article to havedesirable visible transmission characteristics and/or good durability(mechanical and/or chemical). Unfortunately, certain known steps thatare taken to adjust or improve visible transmission characteristicsand/or pre-HT durability tend to degrade post-HT durability and thermalstability. Thus, it is often difficult to obtain a combination ofdesirable visible transmission values, thermal stability of color, andgood durability.

In view of the above, it will be apparent to those skilled in the artthat there exists a need for a low-E coating or layer system that afterHT substantially matches in color and/or reflection (as viewed by anaked human eye) its non-heat treated counterpart. In other words, thereexists a need in the art for a low-E matchable coating or layeringsystem. There also exists a need in the art for a heat treatable systemthat can combine one or more of: (1) desirable visible transmissioncharacteristics (e.g., from about 30-75% measured monolithically, and/orfrom 30-70% as measured in an IG unit), (2) good durability beforeand/or after heat treatment, (3) a low ΔE* value which is indicative ofcolor stability upon heat treatment (HT), and/or (4) an absorber filmdesigned to adjust visible transmission and provide desirable colorationfor the coated article, while maintaining durability and/or thermalstability.

It is a purpose of this invention to fulfill one or more of theabove-listed needs, and/or other needs which will become more apparentto the skilled artisan once given the following disclosure.

SUMMARY

An example object of this invention is to provide a low-E coating orlayer system that has good color stability (a low ΔE* value) upon heattreatment (HT). Another example object of this invention is to provide alow-E matchable coating or layering system. Another example object, incertain example embodiments, is to provide an absorber film in the low-Ecoating which is designed to adjust visible transmission and providedesirable coloration for the coated article, while maintainingdurability and/or thermal stability.

Example embodiments of this invention relate to low-E coated articlesthat have approximately the same color characteristics as viewed by thenaked eye both before and after heat treatment (e.g., thermaltempering), and corresponding methods. Such articles may in certainexample embodiments combine two or more of: (1) desirable visibletransmission characteristics, (2) good durability before and/or afterheat treatment, (3) a low ΔE* value which is indicative of colorstability upon heat treatment (HT), and/or (4) an absorber film designedto adjust visible transmission and provide desirable coloration for thecoated article, while maintaining durability and/or thermal stability.

In certain example embodiments, the optional absorber film may be amulti-layer absorber film including a first layer of or including silver(Ag), and a second layer of or including NiCr which may be partially orfully oxided (NiCrO_(x)). Such a multi-layer absorber film may thus, incertain example embodiments, be made up of a layer sequence ofAg/NiCrO_(x). This layer sequence may be repeated in certain exampleinstances. The silver based layer in the absorber film is preferablysufficiently thin so that its primary function is to absorb visiblelight and provide desirable coloration (as opposed to being much thickerand primarily function as an IR reflection layer). The NiCr or NiCrO_(x)is provided over and contacting the silver of the absorber film in orderto protect the silver, and also to contribute to absorption.

A single layer of NiCr (or other suitable material) may also be used asan absorber film in low-E coatings in certain example embodiments ofthis invention. However, it has surprisingly been found that usingsilver in an absorber film (single layer, or multi-layer, absorber film)provides for several unexpected advantages compared to a single layer ofNiCr as the absorber. First, it has been found that a single layer ofNiCr as the absorber tends to cause yellowish coloration in certainlow-E coating coated articles, which may not be desirable in certaininstances. In contrast, it has been surprisingly found that using silverin an absorber films tends to avoid such yellowish coloration and/orinstead provide for more desirable neutral coloration of the resultingcoated article. Thus, the use of silver in an absorber film has beenfound to provide for improved optical characteristics. Second, the useof a single layer of NiCr as the absorber tends to also involveproviding silicon nitride based layers on both sides of the NiCr so asto directly sandwich and contact the NiCr therebetween. It has beenfound that the provision of silicon nitride in certain locations in acoating stack may lead to compromised thermal stability upon HT. Incontrast, it has been surprisingly found that when using silver in anabsorber film a pair of immediately adjacent silicon nitride layers arenot needed, so that thermal stability upon HT may be improved. Thus, theuse of silver in an absorber film has been found to provide for improvedthermal stability including lower ΔE* values and therefor improvedmatchability between HT and non-HT versions of the same coating. The useof silver in an absorber film may also provide for improvedmanufacturability in certain situations.

In certain example embodiments, surprisingly, and unexpectedly, it hasbeen found that the provision of an as-deposited crystalline orsubstantially crystalline (e.g., at least 50% crystalline, morepreferably at least 60% crystalline) layer of or including zinc oxide,doped with at least one dopant (e.g., Sn), immediately under an infrared(IR) reflecting layer of or including silver in a low-E coating haseffect of significantly improving the coating's thermal stability (i.e.,lowering the ΔE* value). One or more such crystalline, or substantiallycrystalline (e.g., at least 50% crystalline, more preferably at least60% crystalline), layers may be provided under one or more correspondingIR reflecting layers comprising silver, in various embodiments of thisinvention. Thus, the crystalline or substantially crystalline layer ofor including zinc oxide, doped with at least one dopant (e.g., Sn),immediately under an infrared (IR) reflecting layer of or includingsilver may be used in single silver low-E coatings, double-silver low-Ecoatings, or triple silver low-E coatings in various embodiments of thisinvention. In certain example embodiments, the crystalline orsubstantially crystalline layer of or including zinc oxide is doped withfrom about 1-30% Sn, more preferably from about 1-20% Sn, mostpreferably from about 5-15% Sn, with an example being about 10% Sn (interms of wt. %). The zinc oxide, doped with Sn, is in a crystallized orsubstantially crystallized phase (as opposed to amorphous ornanocrystalline) as deposited, such as via sputter deposition techniquesfrom at least one sputtering target(s) of or including Zn and Sn. Thecrystallized phase of the doped zinc oxide based layer as deposited,combined with the layer(s) between the silver and the glass, allows thecoated article to realize improved thermal stability upon optional HT(lower the ΔE* value). It is believed that the crystallized phase of thedoped zinc oxide based layer as deposited (e.g., at least 50%crystalline, more preferably at least 60% crystalline), combined withthe layer(s) between the IR reflecting layer and the glass, allows thesilver of the IR reflecting layer to have improved crystal structurewith texture but with some randomly oriented grains so that itsrefractive index (n) changes less upon optional HT, thereby allowing forimproved thermal stability to be realized.

In certain example embodiments, it has also been surprisingly andunexpectedly found that the provision of a dielectric layer(s) of orincluding silicon oxide, zirconium oxide, zirconium oxynitride, siliconzirconium oxide and/or silicon zirconium oxynitride (e.g., SiZrO_(x),ZrO₂, SiO₂, and/or SiZrO_(x)N_(y)) also provides for improved thermalstability of the coated article, and thus lower the ΔE* values upon heattreatment (HT) such as thermal tempering. In certain exampleembodiments, at least one dielectric layer(s) of or including siliconoxide, zirconium oxide, silicon zirconium oxide and/or silicon zirconiumoxynitride (e.g., SiZrO_(x), ZrO₂, SiO₂, and/or SiZrO_(x)N_(y)) may beprovided: (i) in the bottom dielectric portion of the coating under allsilver based IR reflecting layer(s), and/or (ii) in a middle dielectricportion of the coating between a pair of silver based IR reflectinglayers. For example, the dielectric layer of or including silicon oxide,zirconium oxide, silicon zirconium oxide and/or silicon zirconiumoxynitride may be provided directly under and contacting the lowermostdoped zinc oxide based layer in certain example embodiments of thisinvention, and/or between a pair of zinc oxide inclusive layers in amiddle dielectric portion of the low-E coating.

The dielectric layer(s) of or including silicon oxide, zirconium oxide,silicon zirconium oxide and/or silicon zirconium oxynitride may or maynot be provided in combination with an as-deposited crystalline orsubstantially crystalline (e.g., at least 50% crystalline, morepreferably at least 60% crystalline) layer(s) of or including zincoxide, doped with at least one dopant (e.g., Sn), immediately under aninfrared (IR) reflecting layer, in various example embodiments of thisinvention.

In certain example embodiments, it has surprisingly and unexpectedlybeen found that initially sputter-depositing the dielectric layer(s) ofor including zirconium oxide (e.g., ZrO₂), zirconium oxynitride, siliconzirconium oxide and/or silicon zirconium oxynitride (e.g., SiZrO_(x),ZrO₂, SiO₂, and/or SiZrO_(x)N_(y)) so as to comprise a monoclinic phasecrystalline structure is advantageous in that it results in improvedthermal stability (lower ΔE* value) and/or reduced change in visibletransmission (e.g., T_(vis) or TY) of the coated article upon heattreatment (HT). In certain example embodiments, the monoclinic phase forthe dielectric layer (e.g., ZrO₂) may be achieved by using a very highoxygen gas flow for that layer during the sputter-deposition process ofthat layer, and using a metallic sputtering target (e.g., Zr target).For example, when sputter depositing layer 2 and/or 2″ to form a layerhaving monoclinic phase, the sputter process for that layer mayimplement an oxygen gas flow of at least 5 ml/kW, more preferably of atleast 6 ml/kW, more preferably at least 8 ml/kW, and most preferably atleast 10 ml/kW, where ml indicates the total oxygen gas flow in thechamber and kW indicates power to the target. It is noted that such highoxygen gas flows desired in certain example embodiments of this case arecounterintuitive, and conventionally undesirable, because they reducedeposition rates and thus created added time and expense in makingcoated articles. While high oxygen gas flows are used to achieve themonoclinic phase in connection with metal targets in certain exampleembodiments when certain types of sputtering equipment is used, thisinvention is not so limited, as it has been found that with certaintypes of sputtering equipment the monoclinic phase may also be achievedwith low or lower oxygen gas flows.

It has been found that a significant partial or full phase change awayfrom monoclinic to tetragonal or cubic crystalline structure, andcorresponding density change, of the layer upon HT tends to compensatefor change in crystalline structure of the silver layer(s) upon said HT,which appears to result in improved thermal stability (lower ΔE* value)and/or reduced change in visible transmission (e.g., T_(vis) or TY) ofthe coated article upon HT. It has been surprisingly found thatinitially sputter-depositing the dielectric layer(s) of or includingzirconium oxide, zirconium oxynitride, silicon zirconium oxide and/orsilicon zirconium oxynitride (e.g., SiZrO_(x), ZrO₂, SiO₂, and/orSiZrO_(x)N_(y)) so as to comprise a monoclinic phase crystallinestructure is advantageous in that it results in a high density change inthe layer of at least about 0.25 g/cm³, more preferably of at leastabout 0.30 g/cm³, and most preferably of at least about 0.35 g/cm³(e.g., from about 5.7 to about 6.1 g/cm³), upon HT which in turncompensates for change in crystalline structure of the silver layer(s)upon said HT, resulting in improved thermal stability (lower ΔE* value)and/or reduced change in visible transmission (T_(vis) or TY) of thecoated article upon heat treatment (HT). In certain example embodiments,this allows for reduced change in visible transmission (T_(vis) or TY)of the coated article of no more than 1.2%, more preferably no more than1.0%, and most preferably no more than 0.5%, due to HT, and/or a reducedΔE* value.

It has also been surprisingly and unexpectedly found that the provisionof no silicon nitride based layer directly under and contacting thelowermost doped zinc oxide based layer between the glass substrate andthe lowermost silver based layer, in combination with the crystallizedphase of the doped zinc oxide based layer as deposited, allows forimproved thermal stability upon heat treatment (lower ΔE* values) to berealized. It has also been surprisingly and unexpectedly found that theprovision of no silicon nitride based layer in the middle section of thestack between the two silver-based IR reflecting layers allows forimproved thermal stability upon heat treatment (lower ΔE* values) to berealized.

In certain example embodiments, measured monolithically and/or in an IGunit with two panes, the coated article is configured to realize one ormore of: (i) a transmissive ΔE* value (where transmissive optics aremeasured) of no greater than 3.0 (more preferably no greater than 2.8,and most preferably no greater than 2.5 or 2.3) upon HT for 8, 12 and/or16 minutes at a temperature of about 650 degrees C., (ii) a glass sidereflective ΔE* value (where glass side reflective optics are measured)of no greater than 3.0 (more preferably no greater than 2.5, morepreferably no greater than 2.0, and most preferably no greater than 1.5,no greater than 1.0, and/or no greater than 0.6) upon HT for 8, 12and/or 16 minutes at a temperature of about 650 degrees C., and/or (iii)a film side reflective ΔE* value (where film side reflective optics aremeasured) of no greater than 3.5 (more preferably no greater than 3.0,and most preferably no greater than 2.0, or no greater than 1.5, or 1.3)upon HT for 8, 12, 16 and/or 20 minutes at a temperature of about 650degrees C. Of course, in commercial practice the baking times may be fordifferent/other time periods, and these are for reference purposes. Incertain example embodiments, measured monolithically, the coated articleis configured to have a visible transmission (T_(vis) or Y), before orafter any optional HT, of at least about 30%, more preferably of atleast about 40%, and most preferably of at least about 50% (e.g., fromabout 45-60%). Coated articles herein may have, for example, visibletransmission from about 30-75% measured monolithically, and/or from30-70% as measured in an IG unit. Among other things, the thickness,makeup, and/or number of layers of the absorber may be adjusted toadjust visible transmission. In certain example embodiments, measuredmonolithically, the coated article is configured to have a glass sidevisible reflection (R_(g)Y or RGY), measured monolithically, before orafter any optional HT, of no greater than about 20%.

In an example embodiment of this invention, there is provided a coatedarticle including a coating on a glass substrate, wherein the coatingcomprises: a first crystalline or substantially crystalline layercomprising zinc oxide doped with from about 1-30% Sn (wt. %), providedon the glass substrate; a first infrared (IR) reflecting layercomprising silver located on the glass substrate and directly over andcontacting the first crystalline or substantially crystalline layercomprising zinc oxide doped with from about 1-30% Sn; wherein no siliconnitride based layer is located directly under and contacting the firstcrystalline or substantially crystalline layer comprising zinc oxidedoped with from about 1-30% Sn; at least one dielectric layer havingmonoclinic phase and comprising an oxide of zirconium; wherein the atleast one dielectric layer having monoclinic phase and comprising theoxide of zirconium is located: (1) between at least the glass substrateand the first crystalline or substantially crystalline layer comprisingzinc oxide doped with from about 1-30% Sn (wt. %), and/or (2) between atleast the first IR reflecting layer comprising silver and a second IRreflecting layer comprising silver of the coating; an optional absorberfilm including a layer comprising silver, wherein a ratio of a physicalthickness of the first IR reflecting layer comprising silver to aphysical thickness of the layer comprising silver of the absorber filmis at least 5:1 (more preferably at least 8:1, even more preferably atleast 10:1, and most preferably at least 15:1); and wherein the coatedarticle is configured to have, measured monolithically, at least two of:(i) a transmissive ΔE* value of no greater than 3.0 due to a referenceheat treatment for 12 minutes at a temperature of about 650 degrees C.,(ii) a glass side reflective ΔE* value of no greater than 3.0 due to thereference heat treatment for 12 minutes at a temperature of about 650degrees C., and (iii) a film side reflective ΔE* value of no greaterthan 3.5 due to the reference heat treatment for 12 minutes at atemperature of about 650 degrees C.

Such coated articles may be used monolithically for windows, ininsulating glass (IG) window units (e.g., on surface #2 or surface #3 inIG window unit applications), laminated window units, vehiclewindshields, and/or other vehicle or architectural or residential windowapplications.

This invention will now be described with respect to certain embodimentsthereof as illustrated in the following drawings, wherein:

IN THE DRAWINGS

FIGS. 1(a), 1(b), 1(c), 1(d), 1(e), 1(f), 1(g), 1(h), and 1(i) are crosssectional views of coated articles according to example embodiments ofthis invention.

FIG. 2 is a chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 1 on a 6 mm thickglass substrate, where the low-E coating is illustrated in general byFIG. 1(a).

FIG. 3 is a chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 2 on a 6 mm thickglass substrate, where the low-E coating is illustrated in general byFIG. 1(a).

FIG. 4 is a chart illustrating optical characteristics of Example 1: ascoated (annealed) before heat treatment in the left-most data column,after 12 minutes of heat treatment at 650 degrees C. (HT), after 16minutes of HT at 650 degrees C. (HTX), and after 24 minutes of heattreatment at 650 degrees C. (HTXXX) in the far right data column.

FIG. 5 is a chart illustrating optical characteristics of Example 2: ascoated (annealed) before heat treatment in the left-most data column,after 12 minutes of heat treatment at 650 degrees C. (HT), after 16minutes of HT at 650 degrees C. (HTX), and after 24 minutes of heattreatment at 650 degrees C. (HTXXX) in the far right data column.

FIG. 6 is a chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 3 on a 3.1 mm thickglass substrate, where the low-E coating is illustrated in general byFIG. 1(a).

FIG. 7 is a chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 4 on a 3.1 mm thickglass substrate, where the low-E coating is illustrated in general byFIG. 1(a).

FIG. 8 is a chart illustrating optical characteristics of Examples 3-4:as coated (annealed) before heat treatment in the left-most data column,after 8 minutes of heat treatment at 650 degrees C. (HT), after 12minutes of HT at 650 degrees C. (HTX), and after 20 minutes of heattreatment at 650 degrees C. (HTXXX) in the far right data column.

FIG. 9 is a chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 5 on a 6 mm thickglass substrate, where the low-E coating is illustrated in general byFIG. 1(a).

FIG. 10 is a chart illustrating optical characteristics of Example 5: ascoated (annealed) before heat treatment in the left-most data column,after 12 minutes of heat treatment at 650 degrees C. (HT), after 16minutes of HT at 650 degrees C. (HTX), and after 24 minutes of heattreatment at 650 degrees C. (HTXXX) in the far right data column.

FIG. 11 is a chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 6 on a 6 mm thickglass substrate, where the low-E coating is illustrated in general byFIG. 1(a).

FIG. 12 is a chart illustrating optical characteristics of Example 6: ascoated (annealed) before heat treatment in the left-most data column,after 12 minutes of heat treatment at 650 degrees C. (HT), after 16minutes of HT at 650 degrees C. (HTX), and after 24 minutes of heattreatment at 650 degrees C. (HTXXX) in the far right data column.

FIG. 13 is chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 7 on a 6 mm thickglass substrate, where the low-E coating is illustrated in general byFIG. 1(a).

FIG. 14 is a chart illustrating optical characteristics of Example 7: ascoated (annealed) before heat treatment in the left-most data column,after 12 minutes of heat treatment at 650 degrees C. (HT), after 16minutes of HT at 650 degrees C. (HTX), and after 24 minutes of heattreatment at 650 degrees C. (HTXXX) in the far right data column.

FIG. 15 is a chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 8 on a 6 mm thickglass substrate, where the low-E coating is illustrated in general byFIG. 1(a).

FIG. 16 is a wavelength (nm) vs. refractive index (n) graph illustratingthe change in refractive index of the silver layer of Example 8 from theas coated (AC) state to the heat treated (HT) state.

FIG. 17 is a chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 9 on a 6 mm thickglass substrate, where the low-E coating is illustrated in general byFIG. 1(a).

FIG. 18 is a chart illustrating optical characteristics of Example 9: ascoated (annealed) before heat treatment in the left-most data column,after 12 minutes of heat treatment at 650 degrees C. (HT), and after 16minutes of HT at 650 degrees C. (HTX) in the far right data column.

FIG. 19 is a cross sectional view of a first Comparative Example coatedarticle.

FIG. 20 is a cross sectional view of a coated article according to anembodiment of this invention, illustrating coatings of Examples 1-10.

FIG. 21 is chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 10 on a 3.1 mm thickglass substrate, where the low-E coating is illustrated in general byFIGS. 1(a) and 10.

FIG. 22 is an XRD Lin (Cps) vs. 2-Theta-Scale graph illustrating, forExample 10, the relative small 66% change in peak height of Ag (111) dueto HT.

FIG. 23 is an XRD Lin (Cps) vs. 2-Theta-Scale graph illustrating, forthe first Comparative Example (CE), the relative large 166% change inpeak height of Ag (111) due to HT.

FIG. 24 is a chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 11 on a 6 mm thickglass substrate, where the low-E coating is illustrated in general byFIG. 1(b).

FIG. 25 is a chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 12 on a 6 mm thickglass substrate, where the low-E coating is illustrated in general byFIG. 1(b).

FIG. 26 is a chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 13 on a 6 mm thickglass substrate, where the low-E coating is illustrated in general byFIG. 1(b).

FIG. 27 is a chart illustrating optical characteristics of Examples11-13: as coated (annealed) before heat treatment in the left-most datacolumn of each, after 12 minutes of heat treatment at 650 degrees C.(HT), after 16 minutes of HT at 650 degrees C. (HTX), and after 24minutes of heat treatment at 650 degrees C. (HTXXX) in the far rightdata column of each.

FIG. 28 is a chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Example 14 on a 6 mm thickglass substrate, where the low-E coating is illustrated in general byFIG. 1(b).

FIG. 29 is a chart illustrating optical characteristics of Example 14:as coated (annealed) before heat treatment in the left-most data column,after 12 minutes of heat treatment at 650 degrees C. (HT), after 16minutes of HT at 650 degrees C. (HTX), and after 24 minutes of heattreatment at 650 degrees C. (HTXXX) in the far right data column.

FIG. 30 is chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coatings of Examples 15 and 16 on 6 mmthick glass substrates, where the low-E coatings of these examples areillustrated in general by FIG. 1(b) with a bottommost dielectric layerof ZrO₂.

FIG. 31 is a chart illustrating optical characteristics of Examples 15and 16: as coated (annealed) before heat treatment in the left-most datacolumn, after 12 minutes of heat treatment at 650 degrees C. (HT), andafter 16 minutes of HT at 650 degrees C. (HTX) in the far right datacolumn.

FIG. 32 is a chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coatings of Examples 17 and 18 on 6 mmthick glass substrates, where the low-E coatings of these examples areillustrated in general by FIG. 1(b) with a bottommost dielectric layerof SiO₂ doped with about 8% Al (wt. %)

FIG. 33 is a chart illustrating optical characteristics of Examples 17and 18: as coated (annealed) before heat treatment in the left-most datacolumn, after 12 minutes of heat treatment at 650 degrees C. (HT), andafter 16 minutes of HT at 650 degrees C. (HTX) in the far right datacolumn.

FIG. 34 is chart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Comparative Example 2 (CE 2)on a 6 mm thick glass substrate.

FIG. 35 is a chart illustrating optical characteristics of ComparativeExample 2 (CE 2): as coated (annealed) before heat treatment in theleft-most data column, after 12 minutes of heat treatment at 650 degreesC. (HT), after 16 minutes of HT at 650 degrees C. (HTX), and after 24minutes of heat treatment at 650 degrees C. (HTXXX) in the far rightdata column.

FIG. 36 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 19 on a 6 mmthick glass substrate where the low-E coating is illustrated in generalby FIG. 1(b), and at the bottom portion illustrates opticalcharacteristics of Example 19: as coated (annealed; AC) before heattreatment, after 12 minutes of heat treatment at 650 degrees C. (HT),after 16 minutes of HT at 650 degrees C. (HTX), and after 24 minutes ofheat treatment at 650 degrees C. (HTXXX).

FIG. 37 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 20 on a 6 mmthick glass substrate where the low-E coating is illustrated in generalby FIG. 1(e), and at the bottom portion illustrates opticalcharacteristics of Example 20: as coated (annealed; AC) before heattreatment, after 12 minutes of heat treatment at 650 degrees C. (HT),after 16 minutes of HT at 650 degrees C. (HTX), and after 24 minutes ofheat treatment at 650 degrees C. (HTXXX).

FIG. 38 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 21 on a 6 mmthick glass substrate where the low-E coating is illustrated in generalby FIG. 1(e), and at the bottom portion illustrates opticalcharacteristics of Example 21: as coated (annealed; AC) before heattreatment, after 12 minutes of heat treatment at 650 degrees C. (HT),after 16 minutes of HT at 650 degrees C. (HTX), and after 24 minutes ofheat treatment at 650 degrees C. (HTXXX).

FIG. 39 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 22 on a 6 mmthick glass substrate where the low-E coating is illustrated in generalby FIG. 1(d), and at the bottom portion illustrates opticalcharacteristics of Example 22: as coated (annealed; AC) before heattreatment, after 12 minutes of heat treatment at 650 degrees C. (HT),after 16 minutes of HT at 650 degrees C. (HTX), and after 24 minutes ofheat treatment at 650 degrees C. (HTXXX).

FIG. 40 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 23 on a 6 mmthick glass substrate where the low-E coating is illustrated in generalby FIG. 1(f), and at the bottom portion illustrates opticalcharacteristics of Example 23: as coated (annealed; AC) before heattreatment, after 12 minutes of heat treatment at 650 degrees C. (HT),after 16 minutes of HT at 650 degrees C. (HTX), and after 24 minutes ofheat treatment at 650 degrees C. (HTXXX).

FIG. 41 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 24 on a 6 mmthick glass substrate where the low-E coating is illustrated in generalby FIG. 1(f), and at the bottom portion illustrates opticalcharacteristics of Example 24: as coated (annealed; AC) before heattreatment, after 12 minutes of heat treatment at 650 degrees C. (HT),after 16 minutes of HT at 650 degrees C. (HTX), and after 24 minutes ofheat treatment at 650 degrees C. (HTXXX).

FIG. 42 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 25 on a 6 mmthick glass substrate where the low-E coating is illustrated in generalby FIG. 1(g), and at the bottom portion illustrates opticalcharacteristics of Example 25: as coated (annealed; AC) before heattreatment, after 12 minutes of heat treatment at 650 degrees C. (HT),after 16 minutes of HT at 650 degrees C. (HTX), and after 24 minutes ofheat treatment at 650 degrees C. (HTXXX).

FIG. 43 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 26 on a 6 mmthick glass substrate where the low-E coating is illustrated in generalby FIG. 1(h), and at the bottom portion illustrates opticalcharacteristics of Example 26: as coated (annealed; AC) before heattreatment, after 12 minutes of heat treatment at 650 degrees C. (HT),after 16 minutes of HT at 650 degrees C. (HTX), and after 24 minutes ofheat treatment at 650 degrees C. (HTXXX).

FIG. 44 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 27 on a 6 mmthick glass substrate where the low-E coating is illustrated in generalby FIG. 1(b), and at the bottom portion illustrates opticalcharacteristics of Example 27: as coated (annealed; AC) before heattreatment, after 12 minutes of heat treatment at 650 degrees C. (HT),after 16 minutes of HT at 650 degrees C. (HTX), and after 24 minutes ofheat treatment at 650 degrees C. (HTXXX).

FIG. 45 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 28 on a 6 mmthick glass substrate where the low-E coating is illustrated in generalby FIG. 1(e), and at the bottom portion illustrates opticalcharacteristics of Example 28: as coated (annealed; AC) before heattreatment, after 12 minutes of heat treatment at 650 degrees C. (HT),after 16 minutes of HT at 650 degrees C. (HTX), and after 24 minutes ofheat treatment at 650 degrees C. (HTXXX).

FIG. 46 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 29 on a 6 mmthick glass substrate where the low-E coating is illustrated in generalby FIG. 1(h) except that no layer 2″ is provided in Example 29, and atthe bottom portion illustrates optical characteristics of Example 29: ascoated (annealed; AC) before heat treatment, after 12 minutes of heattreatment at 650 degrees C. (HT), after 16 minutes of HT at 650 degreesC. (HTX), and after 24 minutes of heat treatment at 650 degrees C.(HTXXX).

FIG. 47 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 30 on a 6 mmthick clear glass substrate where the low-E coating is illustrated ingeneral by FIG. 1(i); and at the bottom portion illustrates opticalcharacteristics of Example 30 measured monolithically as coated(annealed; AC) before heat treatment, after 12 minutes of heat treatmentat 650 degrees C. (HT), and after 16 minutes of HT at 650 degrees C.(HTX).

FIG. 48 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 31 on a 6 mmthick clear glass substrate where the low-E coating is illustrated ingeneral by FIG. 1(i); and at the bottom portion illustrates opticalcharacteristics of Example 31 measured monolithically as coated(annealed; AC) before heat treatment, after 12 minutes of heat treatmentat 650 degrees C. (HT), and after 16 minutes of HT at 650 degrees C.(HTX).

FIG. 49 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 32 on a 6 mmthick clear glass substrate where the low-E coating is illustrated ingeneral by FIG. 1(i); and at the bottom portion illustrates opticalcharacteristics of Example 32 measured monolithically as coated(annealed; AC) before heat treatment, after 12 minutes of heat treatmentat 650 degrees C. (HT), and after 16 minutes of HT at 650 degrees C.(HTX).

FIG. 50 illustrates at the top portion sputter-deposition conditions forthe sputter-deposition of the low-E coating of Example 33 on a 6 mmthick clear glass substrate where the low-E coating is illustrated ingeneral by FIG. 1(i); and at the bottom portion illustrates opticalcharacteristics of Example 33 measured monolithically as coated(annealed; AC) before heat treatment, after 12 minutes of heat treatmentat 650 degrees C. (HT), and after 16 minutes of HT at 650 degrees C.(HTX).

FIG. 51 illustrates graphs for sputter-depositing a ZrO₂ layer using ametal Zr target (upper graph) and a ceramic ZrOx target (lower graph),before and after HT, and shows that the layer comprises a monoclinicphase (see the peak at m-ZrO₂) when the metal target was used, but notwhen the ceramic target was used in this particular instance.

FIG. 52 is a cross sectional view of coated articles according toexample embodiments of this invention, similar to FIG. 1(i) in certainrespects, including the layer stack for Examples 34-42 and ComparativeExamples (CEs) 43-47.

FIG. 53 illustrates the optical data of Examples 34-42 as coated (AC;annealed) before heat treatment in the left-most data column of eachexample, and after 12 minutes of heat treatment at 650 degrees C. (HT)in the right data column of each example, Examples 34-42 having acoating stack as shown in FIG. 1(i) and FIG. 52 with monoclinic ZrO₂layers deposited with metal target, and layer thicknesses for Examples34-42 as shown in FIG. 55; where sample 7982 is Example 34, sample 8077is Example 35, sample 8085 is Example 36, sample 8090 is Example 37,sample 8091 is Example 38, sample 8097 is Example 39, sample 8186 isExample 40, sample 8187 is Example 41, and sample 8202 is Example 42.

FIG. 54 illustrates the optical data of Comparative Examples (CEs) 43-47as coated (AC; annealed) before heat treatment in the left-most datacolumn of each example, and after 12 minutes of heat treatment at 650degrees C. (HT) in the right data column of each example, Examples 43-47having a coating stack as shown in FIG. 1(i) and FIG. 52 withnon-monoclinic ZrO₂ layers deposited with ceramic target, and layerthicknesses for Examples 43-47 as shown in FIG. 56; where sample 8392 isCE 43, sample 8394 is CE 44, sample 8395 is CE 45, sample 8396 is CE 46,and sample 8397 is CE 47.

FIG. 55 is a chart illustrating deposition process conditions and layerthicknesses for Example 37 having monoclinic ZrO₂ layers, with totaloxygen flow (ml) during the sputtering process for each layer indicatedby the sum of O₂ setpoint, O₂ tune, and O₂ offset, with the high oxygengas flow during sputter-deposition of the ZrO₂ layers helping providethe monoclinic phase of the ZrO₂ layers of Example 37 (monoclinicExamples 34-36 and 38-42 had similar process conditions).

FIG. 56 is a chart illustrating deposition process conditions and layerthicknesses for Comparative Example (CE) 44 having non-monoclinic ZrO₂layers, with total oxygen flow (ml) during the sputtering process foreach layer indicated by the sum of O₂ setpoint, O₂ tune, and O₂ offset,with the low oxygen gas flow during sputter-deposition of the ZrO₂layers together with ceramic target helping provide the non-monoclinicphase of the ZrO₂ layers of Example 44 (non-monoclinic Examples 43 and45-47 had similar process conditions).

FIG. 57 is a chart illustrating deposition process conditions and layerthicknesses for Example 48 having a monoclinic ZrO₂ layer deposited viaa ceramic target.

FIG. 58 is a chart illustrating ΔE* values for Example 48, withdifferent heat treatment times.

FIG. 59 is a chart illustrating optical data and sheet resistance datafor coatings of Example 48.

DETAILED DESCRIPTION OF CERTAIN EXEMPLARY EMBODIMENTS OF THE INVENTION

Referring now more particularly to the accompanying drawings in whichlike reference numerals indicate like parts/layers/materials throughoutthe several views.

Certain embodiments of this invention provide a coating or layer systemthat may be used in coated articles that may be used monolithically forwindows, in insulating glass (IG) window units (e.g., on surface #2 orsurface #3 in IG window unit applications), laminated window units,vehicle windshields, and/or other vehicle or architectural orresidential window applications. Certain embodiments of this inventionprovide a layer system that combines one or more of high visibletransmission, good durability (mechanical and/or chemical) before and/orafter HT, and good color stability upon heat treatment. It will be shownherein how certain layers stacks surprisingly enable this uniquecombination.

With regard to color stability, certain embodiments of this inventionhave excellent color stability (i.e., a low value of ΔE*; where Δ isindicative of change in view of heat treatment) with heat treatment(e.g., thermal tempering or heat bending) monolithically and/or in thecontext of dual pane environments such as IG units or windshields. Suchheat treatments (HTs) often necessitate heating the coated substrate totemperatures of at least about 1100° F. (593° C.) and up to 1450° F.(788° C.) [more preferably from about 1100 to 1200 degrees F., and mostpreferably from 1150-1200 degrees F.] for a sufficient period of time toinsure the end result (e.g., tempering, bending, and/or heatstrengthening). Certain embodiments of this invention combine one ormore of (i) color stability with heat treatment, and (ii) the use of asilver inclusive layer for selective IR reflection.

Example embodiments of this invention relate to low-E coated articlesthat have approximately the same color characteristics as viewed by thenaked eye both before and after heat treatment (e.g., thermaltempering), and corresponding methods. Such articles may in certainexample embodiments combine one or more of: (1) desirable visibletransmission characteristics, (2) good durability before and/or afterheat treatment, (3) a low ΔE* value which is indicative of colorstability upon heat treatment (HT), and/or (4) an absorber film designedto adjust visible transmission and provide desirable coloration for thecoated article, while maintaining durability and/or thermal stability.

In certain example embodiments, the absorber film may be a multi-layerabsorber film including a first layer 57 of or including silver (Ag),and a second layer 59 of or including NiCr which may be partially orfully oxided (NiCrO_(x)). See FIG. 1(i) for example. Such a multi-layerabsorber film 57, 59 may thus, in certain example embodiments, be madeup of a layer sequence of Ag/NiCrO_(x). Elements from one layer maydiffuse into an adjacent layer due to HT or other factors. The NiCrbased layer 59 of the absorber may be initially deposited in metallicform, or as a suboxide, in certain example embodiments. The silver basedlayer 57 may be a continuous layer, and/or may optionally be doped, incertain example embodiments. Moreover, the silver based layer 57 of theabsorber film is preferably sufficiently thin so that its primaryfunction is to absorb visible light and provide desirable coloration (asopposed to being much thicker and primarily function as an IR reflectionlayer). The NiCr or NiCrO_(x) 59 is provided over and contacting thesilver 57 of the absorber film in order to protect the silver, and alsoto contribute to absorption. In certain example embodiments, the silverbased layer 57 of the absorber film may be no more than about 60 Åthick, more preferably no more than about 30 Å thick, more preferably nogreater than about 20 Å thick, and most preferably no greater than about15 Å thick, and possibly no greater than about 12 Å thick, in certainexample embodiments of this invention. In certain example embodiments,the NiCr based layer 59 of the absorber film may be from about 5-200 Åthick, more preferably from about 10-110 Å thick, and most preferablyfrom about 40-90 Å thick.

A single layer of NiCr (or other suitable material) may also be used asan absorber film in low-E coatings in certain example embodiments ofthis invention. For example, see absorber film 42 in FIGS. 1(d) and1(f). However, it has surprisingly been found that using silver 57 in anabsorber film (single layer, or multi-layer, absorber film) provides forseveral unexpected advantages compared to a single layer of NiCr as theabsorber. First, it has been found that a single layer of NiCr as theabsorber tends to cause yellowish coloration in certain low-E coatingcoated articles, which may not be desirable in certain instances. Incontrast, it has been surprisingly found that using silver 57 in anabsorber films tends to avoid such yellowish coloration and/or insteadprovide for more desirable neutral coloration of the resulting coatedarticle. Thus, the use of silver 57 in an absorber film has been foundto provide for improved optical characteristics. Second, the use of asingle layer of NiCr 42 as the absorber tends to also involve providingsilicon nitride based layers on both sides of the NiCr so as to directlysandwich and contact the NiCr therebetween. For example, see FIGS. 1(d)and 1(f). It has been found that the provision of silicon nitride incertain locations in a coating stack may lead to compromised thermalstability upon HT. In contrast, it has been surprisingly found that whenusing silver in an absorber film a pair of immediately adjacent siliconnitride layers are not needed, so that thermal stability upon HT may beimproved. Thus, the use of silver 57 in an absorber film has been foundto provide for improved thermal stability including lower ΔE* values andtherefor improved matchability between HT and non-HT versions of thesame coating. The use of silver in an absorber film may also provide forimproved manufacturability in certain situations.

Surprisingly, and unexpectedly, it has been found that the provision ofan as-deposited crystalline or substantially crystalline layer 3, 3″(and/or 13) (e.g., at least 50% crystalline, more preferably at least60% crystalline) of or including zinc oxide, doped with at least onedopant (e.g., Sn), immediately under and directly contacting an infrared(IR) reflecting layer of or including silver 7 (and/or 19) in a low-Ecoating 30 has the effect of significantly improving the coating'sthermal stability (i.e., lowering the ΔE* value). “Substantiallycrystalline” as used herein means at least 50% crystalline, morepreferably at least 60% crystalline, and most preferably at least 70%crystalline. One or more such crystalline, or substantially crystalline,layers 3, 3″ 13 may be provided under one or more corresponding IRreflecting layers comprising silver 7, 19, in various exampleembodiments of this invention. Thus, the crystalline or substantiallycrystalline layer 3 (or 3″) and/or 13 of or including zinc oxide, dopedwith at least one dopant (e.g., Sn), immediately under an infrared (IR)reflecting layer 7 and/or 19 of or including silver may be used insingle silver low-E coatings, double-silver low-E coatings (e.g., suchas shown in FIG. 1 or FIG. 20), or triple silver low-E coatings invarious embodiments of this invention. In certain example embodiments,the crystalline or substantially crystalline layer 3 and/or 13 of orincluding zinc oxide is doped with from about 1-30% Sn, more preferablyfrom about 1-20% Sn, more preferably from about 5-15% Sn, with anexample being about 10% Sn (in terms of wt. %). The zinc oxide, dopedwith Sn, is in a crystallized or substantially crystallized phase (asopposed to amorphous or nanocrystalline) in layer 3 and/or 13 asdeposited, such as via sputter deposition techniques from at least onesputtering target(s) of or including Zn and Sn. The crystallized phaseof the doped zinc oxide based layer 3 and/or 13 as deposited, combinedwith the layer(s) between the silver 7 and/or 19 and the glass 1, allowsthe coated article to realize improved thermal stability upon optionalHT (lower the ΔE* value). It is believed that the crystallized phase ofthe doped zinc oxide based layer 3 and/or 13 as deposited, combined withthe layer(s) between the silver and the glass, allows the silver 7and/or 19 deposited thereover to have improved crystal structure withtexture but with some randomly oriented grains so that its refractiveindex (n) changes less upon optional HT, thereby allowing for improvedthermal stability to be realized.

It has also been surprisingly and unexpectedly found that the provisionof a dielectric layer(s) (e.g., 2 and/or 2″) of or including siliconoxide, zirconium oxide, silicon zirconium oxide and/or silicon zirconiumoxynitride (e.g., SiZrO_(x), ZrO₂, SiO₂, and/or SiZrO_(x)N_(y)) alsoprovides for improved thermal stability of the coated article as shownfor example in FIGS. 1(b)-1(i), and thus lower the ΔE* values upon heattreatment (HT) such as thermal tempering. In certain exampleembodiments, at least one dielectric layer (e.g., 2 and/or 2″) of orincluding silicon oxide, zirconium oxide, silicon zirconium oxide and/orsilicon zirconium oxynitride (e.g., SiZrO_(x), ZrO₂, SiO₂, and/orSiZrO_(x)N_(y)) may be provided: (i) in the bottom dielectric portion ofthe coating under all silver based IR reflecting layer(s) (e.g., seeFIGS. 1(b)-1(i)), and/or (ii) in a middle dielectric portion of thecoating between a pair of silver based IR reflecting layers (e.g., seeFIGS. 1(e)-1(i)). For example, the dielectric layer (e.g., 2 and/or 2″)of or including silicon oxide, zirconium oxide, silicon zirconium oxideand/or silicon zirconium oxynitride may be provided directly under andcontacting the lowermost doped zinc oxide based layer (e.g., 3) incertain example embodiments of this invention, and/or between a pair ofzinc oxide inclusive layers (e.g., between 11 and 13, or between 11 and3″) in a middle dielectric portion of the low-E coating.

The dielectric layer(s) (e.g., 2 and/or 2″) of or including siliconoxide (e.g., SiO₂), zirconium oxide (e.g., ZrO₂), silicon zirconiumoxide and/or silicon zirconium oxynitride may or may not be provided incombination with an as-deposited crystalline or substantiallycrystalline (e.g., at least 50% crystalline, more preferably at least60% crystalline) layer(s) (e.g., 3 and/or 13) of or including zincoxide, doped with at least one dopant (e.g., Sn), immediately under aninfrared (IR) reflecting layer, in various example embodiments of thisinvention. Both approaches, which may be used together, but need not beused together, improve thermal stability thereby lowering ΔE* values.For example, in certain embodiments where the dielectric layer(s) (e.g.,2 and/or 2″) of or including silicon oxide (e.g., SiO₂), zirconium oxide(e.g., ZrO₂), silicon zirconium oxide and/or silicon zirconiumoxynitride is used, the contact/seed layer immediately under one or bothsilver(s) may be of or including zinc oxide doped with aluminum (insteadof with Sn) and that contact/seed layer need not be crystalline (e.g.,see FIGS. 42, 43 and 46; and Examples 25, 26 and 29).

In certain example embodiments, it has surprisingly and unexpectedlybeen found that initially sputter-depositing the dielectric layer(s) 2and/or 2″ of or including zirconium oxide, zirconium oxynitride, siliconzirconium oxide and/or silicon zirconium oxynitride (e.g., SiZrO_(x),ZrO₂, SiO₂, and/or SiZrO_(x)N_(y)) so as to comprise a monoclinic phasecrystalline structure is advantageous in that it results in improvedthermal stability (lower ΔE* value) and/or reduced change in visibletransmission (e.g., T_(vis) or TY) of the coated article upon heattreatment (HT). For example, see FIGS. 1(a)-1(i), 51-53, and 55. Thedielectric layer(s) 2 and/or 2″ may, in certain example embodiments,further include other material(s) such as Ti and/or Nb. In certainexample embodiments, the monoclinic phase (e.g., see the m-ZrO₂ peaks inthe upper graph of FIG. 51) for the dielectric layer (e.g., ZrO₂) 2and/or 2″ may be achieved by using a very high oxygen gas flow for thatlayer during the sputter-deposition process of that layer, and using ametallic sputtering target (e.g., metal Zr or SiZr target) (e.g., seeFIG. 55). It is noted that such high oxygen gas flows desired in certainexample embodiments of this case are counterintuitive for zirconiumoxide based layers, and conventionally undesirable, because they reducedeposition rates and thus created added time and expense in makingcoated articles. It has been found that a significant partial or fullphase change away from monoclinic phase (see m-ZrO₂ peaks in the uppergraph of FIG. 51) to tetragonal or cubic crystalline structure (seec-ZrO₂ in FIG. 51), and corresponding density change, of the layer 2and/or 2″ upon HT tends to compensate for change in crystallinestructure of the silver based layer(s) 7, 57, and/or 19 upon said HT,which appears to result in improved thermal stability (lower ΔE* value)and/or reduced change in visible transmission (e.g., T_(vis) or TY) ofthe coated article upon HT. In FIG. 51, note how the monoclinic phase(see m-ZrO₂ peaks in upper graph of in FIG. 51) exists in the top graph(high oxygen flow during deposition, and metal Zr target), but does notexist in the bottom graph (low oxygen flow during deposition, andceramic ZrOx target). And, also in the top graph of FIG. 51, it can beseen how the monoclinic phase (see m-ZrO₂ peaks) is higher before HT,and lower after HT. It has been surprisingly found that initiallysputter-depositing the dielectric layer(s) 2 and/or 2″ of or includingzirconium oxide, zirconium oxynitride, silicon zirconium oxide and/orsilicon zirconium oxynitride (e.g., SiZrO_(x), ZrO₂, SiO₂, and/orSiZrO_(x)N_(y)) so as to comprise a monoclinic phase crystallinestructure is advantageous in that it results in a high density change inthe layer 2 and/or 2″ of at least about 0.25 g/cm³, more preferably ofat least about 0.30 g/cm³, and most preferably of at least about 0.35g/cm³ (e.g., from about 5.7 to about 6.1 g/cm³), due to HT which in turncompensates for change in crystalline structure of the silver basedlayer(s) 7, 19, and/or 57 due to said HT, resulting in improved thermalstability (lower ΔE* value) and/or reduced change in visibletransmission (T_(vis) or TY) of the coated article upon heat treatment(HT). In certain example embodiments, this allows for reduced change invisible transmission (T_(vis) or TY) of the coated article of no morethan 1.2%, more preferably no more than 1.0%, and most preferably nomore than 0.5%, due to HT, and/or a reduced ΔE* value.

It has also surprisingly been found that increased thicknesses for thedielectric layer(s) 2 and/or 2″ of or including silicon oxide, zirconiumoxide, zirconium oxynitride, silicon zirconium oxide and/or siliconzirconium oxynitride (e.g., SiZrO_(x), ZrO₂, SiO₂, and/orSiZrO_(x)N_(y)) tend to result in smaller changes in sheet resistance(R_(s)) and visible transmission upon HT, and thus lower ΔE* values ofthe coated article. In certain example embodiments, one or both of thedielectric layer(s) 2 and/or 2″ of or including silicon oxide, zirconiumoxide, zirconium oxynitride, silicon zirconium oxide and/or siliconzirconium oxynitride (e.g., SiZrO_(x), ZrO₂, SiO₂, and/orSiZrO_(x)N_(y)) may each have a physical thickness of from about 10-400angstroms (Å), more preferably from about 40-170 Å, and most preferablyfrom about 80-140 Å.

It has also been surprisingly and unexpectedly found that the provisionof no silicon nitride based layer (e.g., Si₃N₄, optionally doped with1-10% Al or the like) directly under and contacting the lowermost dopedzinc oxide based layer 3 between the glass substrate 1 and the lowermostsilver based layer 7, in combination with the crystallized orsubstantially crystallized phase of the doped zinc oxide based layer 3as deposited, allows for improved thermal stability upon heat treatment(lower ΔE* values) to be realized. For example, see the coatings ofFIGS. 1(a)-1(d) and 1(i). Moreover, in certain example embodiments,there is no amorphous or substantially amorphous layer located betweenthe glass substrate 1 and the first IR reflecting layer comprisingsilver 7. It has also been surprisingly and unexpectedly found that theprovision of no silicon nitride based layer in the middle section of thestack between the two silver-based IR reflecting layers 7 and 19 allowsfor improved thermal stability upon heat treatment (lower ΔE* values) tobe realized (e.g., see FIGS. 1(a)-1(i)).

In certain example embodiments, it has also been found that providing anabsorber layer (e.g., NiCr, NiCrN_(x), NbZr, and/or NbZrN_(x)) 42between the glass substrate and the dielectric layer 2 of or includingsilicon oxide, zirconium oxide, silicon zirconium oxide and/or siliconzirconium oxynitride (e.g., SiZrO_(x), ZrO₂, SiO₂, and/orSiZrO_(x)N_(y)) may advantageously reduce glass side visible reflection(R_(g)Y) of the coated article in a desirable manner and allows thevisible transmission to be tuned in a desirable manner. The absorberlayer 42 may be provided between and contacting a pair of siliconnitride based layers 41 and 43 (e.g., of or including Si₃N₄, optionallydoped with 1-10% Al or the like, and optionally including from 0-10%oxygen) in certain example embodiments, such as shown in FIGS. 1(d) and1(f) for instance. See also FIG. 39 and Example 22 for instance. Inother example embodiments, the stack made up of the absorber layer 42,between nitride based dielectric layers 41 and 43, may be located atother position(s) within the stack.

In certain example embodiments, measured monolithically, in view of theabove structure (e.g., see FIGS. 1(a)-1(i)), the coated article isconfigured to realize one or more of: (i) a transmissive ΔE* value(where transmissive optics are measured) of no greater than 3.0 (morepreferably no greater than 2.8, or 2.5, and most preferably no greaterthan 2.3) upon HT for 8, 12 and/or 16 minutes at a temperature of about650 degrees C., (ii) a glass side reflective ΔE* value (where glass sidereflective optics are measured) of no greater than 3.0 (more preferablyno greater than 2.5, more preferably no greater than 2.0, even morepreferably no greater than 1.5, and most preferably no greater than 1.0,or 0.6) upon HT for 8, 12 and/or 16 minutes at a temperature of about650 degrees C., and/or (iii) a film side reflective ΔE* value (wherefilm side reflective optics are measured) of no greater than 3.5 (morepreferably no greater than 3.0, and most preferably no greater than 2.0,more preferably no greater than 1.5, and possibly no greater than 1.2)upon HT for 8, 12 and/or 16 minutes at a temperature of about 650degrees C.

In certain example embodiments, measured monolithically, the coatedarticle is configured to have a visible transmission (T_(vis) or Y),before or after any optional HT, of at least about 30%, more preferablyof at least about 35%, more preferably of at least about 40%, morepreferably of at least about 50%. In certain example embodiments, thelow-E coating has a sheet resistance (SR or R_(s)) of no greater than 20ohms/square, more preferably no greater than 10 ohms/square, and mostpreferably no greater than 2.5 or 2.2 ohms/square, before and/or afteroptional heat treatment. In certain example embodiments, the low-Ecoating has a hemispherical emissivity/emittance (Eh) of no greater than0.08, more preferably no greater than 0.05, and most preferably nogreater than 0.04. The value ΔE* is important in determining whether ornot upon heat treatment (HT) there is matchability, or substantialmatchability, in the context of this invention. Color herein isdescribed by reference to the conventional a*, b* values, which incertain embodiments of this invention are both negative in order toprovide color in the desired substantially neutral color range tendingto the blue-green quadrant. For purposes of example, the term Δa* issimply indicative of how much color value a* changes due to heattreatment.

The term ΔE* (and ΔE) is well understood in the art and is reported,along with various techniques for determining it, in ASTM 2244-93 aswell as being reported in Hunter et. al., The Measurement of Appearance,2nd Ed. Cptr. 9, page 162 et seq. [John Wiley & Sons, 1987]. As used inthe art, ΔE* (and ΔE) is a way of adequately expressing the change (orlack thereof) in reflectance and/or transmittance (and thus colorappearance, as well) in an article after or due to heat treatment. ΔEmay be calculated by the “ab” technique, or by the Hunter technique(designated by employing a subscript “H”). ΔE corresponds to the HunterLab L, a, b scale (or L_(h), a_(h), b_(h)). Similarly, ΔE* correspondsto the CIE LAB Scale L*, a*, b*. Both are deemed useful, and equivalentfor the purposes of this invention. For example, as reported in Hunteret. al. referenced above, the rectangular coordinate/scale technique(CIE LAB 1976) known as the L*, a*, b* scale may be used, wherein:

-   -   L* is (CIE 1976) lightness units    -   a* is (CIE 1976) red-green units    -   b* is (CIE 1976) yellow-blue units

and the distance ΔE* between L*_(o) a*_(o) b*_(o) and L*₁ a*₁ b*₁ is:

ΔE*=[(ΔL*)²+(Δa*)²+(Δb*)²]^(1/2)  (1)

where:

ΔL*=L* ₁ −L* _(o)  (2)

Δa*=a* ₁ −a* _(o)  (3)

Δb*=b* ₁ −b* _(o)  (4)

where the subscript “o” represents the coated article before heattreatment and the subscript “1” represents the coated article after heattreatment; and the numbers employed (e.g., a*, b*, L*) are thosecalculated by the aforesaid (CIE LAB 1976) L*, a*, b* coordinatetechnique. In a similar manner, ΔE may be calculated using equation (1)by replacing a*, b*, L* with Hunter Lab values a_(h), b_(h), L_(h). Alsowithin the scope of this invention and the quantification of ΔE* are theequivalent numbers if converted to those calculated by any othertechnique employing the same concept of ΔE* as defined above.

In certain example embodiments of this invention, the low-E coating 30includes two silver-based IR reflecting layers (e.g., see FIGS.1(a)-1(i)), although this invention is not so limited in all instances(e.g., three silver based IR reflecting layers can be used in certaininstances). It will be recognized that the coated articles of FIGS.1(a)-1(i) are illustrated in monolithic form. However, these coatedarticles may also be used in IG window units for example.

Because of materials stability, baking at high temperature (e.g.,580-650 degrees C.) causes change to chemical compositions,crystallinity and microstructures or even phases of dielectric layermaterials. High temperature also causes interface diffusion or evenreaction, as a consequence composition, roughness and index change atinterface locations. As a result, optical properties such as index n/kand optical thickness change upon heat treatment. The IR materials, forexample Ag, have undergone change too. Typically, Ag materials gothrough crystallization, grain growth or even orientation change uponheat treatment. These changes often cause conductivity and particularlyindex n/k changes which have big impact to the optical and thermalproperties of a low-E coating. In addition, the dielectric and thechange of dielectrics also has a significant impact on IR reflectinglayers such as silver undergoing heat treatment. Moreover, silver mayhave more change in one layer stack than in others merely because of thematerials and the layer stacks themselves. If the silver changes arebeyond some limit, then it may not be acceptable aesthetically afterheat treatment. We have found that to get thermal stability of a low-Ecoating, doped zinc oxide crystallized materials on glass eitherdirectly or indirectly with a thin modification layer(s) may be usedunder silver of an IR reflecting layer. Crystalline or substantiallycrystalline doped zinc oxide in these locations has been found to changeless during heat treatment, and result in smaller silver changes withrespect to properties such as indices (e.g., n and/or k) and thus lessoverall color change upon heat treatment.

FIG. 1(a) is a side cross sectional view of a coated article accordingto an example non-limiting embodiment of this invention, where the low-Ecoating 30 has two silver-based IR reflecting layers 7 and 19. Thecoated article includes substrate 1 (e.g., clear, green, bronze, orblue-green glass substrate from about 1.0 to 10.0 mm thick, morepreferably from about 3.0 mm to 8.0 mm thick), and low-E coating (orlayer system) 30 provided on the substrate 1 either directly orindirectly. The coating (or layer system) 30 includes, in FIG. 1(a) forexample: dielectric layer 3 of or including zinc oxide, doped with atleast one metal dopant (e.g., Sn and/or Al), which is crystalline orsubstantially crystalline as deposited; infrared (IR) reflecting layerof or including silver 7 located over and directly contacting layer 3;contact layer 9 of or including Ni and/or Cr (e.g., NiCr, NiCrO_(x),NiCrN_(x), NiCrON, NiCrM, NiCrMoO_(x), etc.), Ti, or other suitablematerial, over and directly contacting the IR reflecting layer 7;dielectric layer 11 of or including zinc stannate (e.g., ZnSnO, Zn₂SnO₄,or other suitable stoichiometry) or other suitable material, which maybe amorphous or substantially amorphous as deposited; another dielectriclayer 13 of or including zinc oxide, doped with at least one dopant(e.g., Sn), which is crystalline or substantially crystalline asdeposited; another infrared (IR) reflecting layer of or including silver19 located over and directly contacting layer 13; another contact layer21 of or including Ni and/or Cr (e.g., NiCr, NiCrO_(x), NiCrN_(x),NiCrON, NiCrM, NiCrMoO_(x), etc.), Ti, or other suitable material, overand directly contacting the IR reflecting layer 19; another dielectriclayer 23 of or including zinc stannate (e.g., ZnSnO, Zn₂SnO₄, or othersuitable stoichiometry) or other suitable material such as tin oxide,which may be amorphous or substantially amorphous as deposited; andamorphous or substantially amorphous dielectric layer 25 of or includingsilicon nitride (e.g., Si₃N₄, or other suitable stoichiometry) which mayoptionally be doped with Al and/or O. The layers shown in FIG. 1(a) maybe deposited by sputter-deposition or in any other suitable manner.

As explained herein, it has been found that the presence of as-depositedcrystalline or substantially crystalline layer 3 and/or 13 of orincluding zinc oxide, doped with at least one dopant (e.g., Sn),immediately under and directly contacting an infrared (IR) reflectinglayer of or including silver 7 and/or 19 in a low-E coating 30 has theeffect of significantly improving the coating's thermal stability (i.e.,lowering the ΔE* value). In certain example embodiments, the crystallineor substantially crystalline layer 3 and/or 13 of or including zincoxide is doped with from about 1-30% Sn, more preferably from about1-20% Sn, more preferably from about 5-15% Sn, with an example beingabout 10% Sn (in terms of wt. %).

In certain example embodiments, the dielectric zinc stannate (e.g.,ZnSnO, Zn₂SnO₄, or the like) based layers 11 and 23 may be deposited inan amorphous or substantially amorphous state (it/they may becomecrystalline or substantially crystalline upon heat treatment). It hasbeen found that having similar amounts of Zn and Sn in the layer, ormore Sn than Zn in the layer, helps ensure that the layer is depositedin an amorphous or substantially amorphous state. For example, the metalcontent of amorphous zinc stannate based layers 11 and 23 may includefrom about 30-70% Zn and from about 30-70% Sn, more preferably fromabout 40-60% Zn and from about 40-60% Sn, with examples being about 52%Zn and about 48% Sn, or about 50% Zn and 50% Sn (weight %, in additionto the oxygen in the layer) in certain example embodiments of thisinvention. Thus, for example, the amorphous or substantially amorphouszinc stannate based layers 11 and/or 23 may be sputter-deposited using ametal target comprising about 52% Zn and about 48% Sn, or about 50% Znand about 50% Sn, in certain example embodiments of this invention.Optionally, the zinc stannate based layers 11 and 23 may be doped withother metals such as Al or the like. Depositing layers 11 and 23 in anamorphous, or substantially amorphous, state, while depositing layers 3and 13 in a crystalline, or substantially crystalline, state, has beenfound to advantageously allow for improved thermal stability to berealized in combination with good optical characteristics such asacceptable transmission, color, and reflection. It is noted that zincstannate layers 11 and/or 23 may be replaced with respective layer(s) ofother material(s) such as tin oxide, zinc oxide, zinc oxide doped withfrom 1-20% Sn (as discussed elsewhere herein regarding layers 11, 13),or the like.

Dielectric layer 25, which may be an overcoat, may be of or includesilicon nitride (e.g., Si₃N₄, or other suitable stoichiometry) incertain embodiments of this invention, in order to improve the heattreatability and/or durability of the coated article. The siliconnitride may optionally be doped with Al and/or O in certain exampleembodiments, and also may be replaced with other material such assilicon oxide or zirconium oxide in certain example embodiments.

Infrared (IR) reflecting layers 7 and 19 are preferably substantially orentirely metallic and/or conductive, and may comprise or consistessentially of silver (Ag), gold, or any other suitable IR reflectingmaterial. IR reflecting layers 7 and 19 help allow the coating to havelow-E and/or good solar control characteristics. The IR reflectinglayers may, however, be slightly oxidized in certain embodiments of thisinvention.

Other layer(s) below or above the illustrated coating in FIG. 1 may alsobe provided. Thus, while the layer system or coating is “on” or“supported by” substrate 1 (directly or indirectly), other layer(s) maybe provided therebetween. Thus, for example, the coating of FIG. 1(a)may be considered “on” and “supported by” the substrate 1 even if otherlayer(s) are provided between layer 3 and substrate 1. Moreover, certainlayers of the illustrated coating may be removed in certain embodiments,while other layer(s) may be added between the various layers or thevarious layer(s) may be split with other layer(s) added between thesplit sections in other embodiments of this invention without departingfrom the overall spirit of certain embodiments of this invention.

While various thicknesses and materials may be used in layers indifferent embodiments of this invention, example thicknesses andmaterials for the respective layers on the glass substrate 1 in the FIG.1(a) embodiment are as follows, from the glass substrate outwardly:

TABLE 1 Example Materials/Thicknesses; FIG. 1(a) Embodiment PreferredRange More Preferred Example Layer Glass ({acute over (Å)}) ({acute over(Å)}) (Å) Sn-doped ZnO 20-900 (or 350-550 {acute over (Å)} 470 Å (layer3) 100-900) {acute over (Å)} Ag (layer 7) 60-260 {acute over (Å)}100-170 {acute over (Å)} 151 Å NiCrO_(x) (layer 9) 10-100 {acute over(Å)} 20-45 {acute over (Å)} 41 Å ZnSnO (layer 11) 200-1200 Å 500-900 Å736 Å Sn-doped ZnO 60-900 {acute over (Å)} 120-400 {acute over (Å)} 177Å (layer 13) Ag (layer 19) 80-280 {acute over (Å)} 140-250 {acute over(Å)} 232 Å NiCrO_(x) (layer 21) 10-100 {acute over (Å)} 20-45 {acuteover (Å)} 41 Å ZnSnO (layer 23) 10-750 Å 70-200 Å 108 Å Si₃N₄ (layer 25)10-750 {acute over (Å)} 100-240 {acute over (Å)} 191 Å

The FIG. 1(b) embodiment is the same as the FIG. 1(a) embodimentdiscussed above and elsewhere herein, except that the low-E coating 30in the FIG. 1(b) embodiment also includes a substantially transparentdielectric layer 2 of or including silicon zirconium oxide, zirconiumoxide, silicon oxide, and/or silicon zirconium oxynitride (e.g.,SiZrO_(x), ZrO₂, SiO₂, SiAlO₂, and/or SiZrO_(x)N_(y)) under and directlycontacting the doped zinc oxide based layer 3. It has been found thatthis additional layer 2 provides for further improved thermal stabilityof the coated article, and thus an even lower the ΔE* value (e.g., alower glass side reflective ΔE* value) upon heat treatment (HT) such asthermal tempering. The dielectric layer 2 of or including siliconzirconium oxide, zirconium oxide, silicon oxide, and/or siliconzirconium oxynitride (e.g., SiZrO_(x), ZrO₂, SiO₂, SiAlO₂, and/orSiZrO_(x)N_(y)) may be provided directly under and contacting thelowermost doped zinc oxide based layer 3 in certain example embodimentsof this invention, as shown in FIG. 1(b). In certain example embodimentsof this invention, dielectric layer 2 of or including silicon zirconiumoxide, zirconium oxide, silicon oxide, and/or silicon zirconiumoxynitride (e.g., SiZrO_(x), ZrO₂, SiO₂, SiAlO₂, and/or SiZrO_(x)N_(y))may be from about 20-600 Å thick, more preferably from about 40-400 Åthick, and most preferably from about 50-300 Å thick. The thicknessesabove for the FIG. 1(a) embodiment may also apply to FIGS. 1(b)-1(i).

When layer 2 (or 2′, or 2″) is of or includes SiZrO_(x) and/orSiZrO_(x)N_(y), it has been found that providing more Si than Zr in thatlayer is advantageous from an optical point of view with a lowrefractive index (n) and improved antireflection and other opticalcharacteristics. For example, in certain example embodiments, when layer2 (or 2′, or 2″) is of or includes SiZrO_(x) and/or SiZrO_(x)N_(y),metal content of the layer may comprise from 51-99% Si, more preferablyfrom 70-97% Si, and most preferably from 80-90% Si, and from 1-49% Zr,more preferably from 3-30% Zr, and most preferably from 10-20% Zr(atomic %). In example embodiments, transparent dielectric layer 2 of orincluding SiZrO_(x) and/or SiZrO_(x)N_(y) may have a refractive index(n), measured at 550 nm, of from about 1.48 to 1.68, more preferablyfrom about 1.50 to 1.65, and most preferably from about 1.50 to 1.62.

The FIG. 1(c) embodiment is the same as the FIG. 1(b) embodimentdiscussed above and elsewhere herein, except that the low-E coating 30in the FIG. 1(c) embodiment also includes a substantially transparentdielectric layer 2′ of or including silicon nitride (e.g., Si₃N₄,optionally doped with 1-10% Al or the like, and optionally includingfrom 0-10% oxygen, or other suitable stoichiometry) and/or siliconzirconium oxynitride, located between and contacting the glass substrate1 and the dielectric layer 2. Layer 2′ may also be of or includingaluminum nitride (e.g., AlN).

The FIG. 1(d) embodiment is the same as the FIG. 1(b) embodimentdiscussed above and elsewhere herein, except that the low-E coating 30in the FIG. 1(d) embodiment also includes a metallic or substantiallymetallic absorber layer 42 sandwiched between and contacting siliconnitride based layers 41 and 43 (e.g., Si₃N₄, optionally doped with 1-10%Al or the like, and optionally including from 0-10% oxygen). Dielectriclayer(s) 41 and/or 43 may also be of or include aluminum nitride (e.g.,AlN) in certain example embodiments. The absorber layer 42 may be of orincluding NiCr, NbZr, Nb, Zr, or nitrides thereof, or other suitablematerial, in example embodiments of this invention. The absorber layer42 preferably contains from 0-10% oxygen (atomic %), more preferablyfrom 0-5% oxygen. In certain example embodiments, it has been found thatproviding an absorber layer (e.g., NiCr, NiCrN_(x), NbZr, and/orNbZrN_(x)) 42 between the glass substrate and the dielectric layer 2 ofor including silicon zirconium oxide, zirconium oxide, silicon oxide,and/or silicon zirconium oxynitride (e.g., SiZrO_(x), ZrO₂, SiO₂,SiAlO₂, and/or SiZrO_(x)N_(y)) advantageously reduces glass side visiblereflection (R_(g)Y) of the coated article in a desirable manner, andallows the visible transmission to be tuned in a desirable manner See,for example, FIG. 39 and Example 22. In certain example embodiments, theabsorber layer 42 may be from about 10-150 Å thick, more preferably fromabout 30-80 Å thick. In certain example embodiments, the silicon nitridebased layers 41 and 43 may be from about 50-300 Å thick, more preferablyfrom about 70-140 Å thick. For instance, in Example 22 and FIG. 39, theabsorber layer 42 is a nitride of NiCr, and is about 1.48 nm thick. Inother example embodiments, the stack made up of the absorber layer 42,between nitride based dielectric layers 41 and 43, may be located atother position(s) within the stack.

Referring to FIGS. 1(a)-1(d), another transparent dielectric layer (notshown) of or including ZrO₂, SiZrO_(x) and/or SiZrO_(x)N_(y) may beprovided either between layers 11 and 13. In certain exampleembodiments, zinc stannate inclusive layer 11 may be omitted, or may bereplaced with such another transparent dielectric layer of or includingZrO₂, SiZrO_(x) and/or SiZrO_(x)N_(y). It is also possible for dopedzinc oxide layer 13 to be split with such another layer transparentdielectric layer of or including ZrO₂, SiZrO_(x) and/or SiZrO_(x)N_(y).For example, in certain example embodiments, when such an additionallayer is of or includes SiZrO_(x) and/or SiZrO_(x)N_(y), metal contentof the layer may comprise from 51-99% Si, more preferably from 70-97%Si, and most preferably from 80-90% Si, and from 1-49% Zr, morepreferably from 3-30% Zr, and most preferably from 10-20% Zr (atomic %),and may contain from 0-20% nitrogen, more preferably from 0-10%nitrogen, and most preferably from 0-5% nitrogen (atomic %). Forinstance, at least one dielectric layer (e.g., 2 and/or 2″) of orincluding silicon oxide, zirconium oxide, zirconium oxynitride, siliconzirconium oxide and/or silicon zirconium oxynitride (e.g., SiZrO_(x),ZrO₂, SiO₂, and/or SiZrO_(x)N_(y)) may be provided: (i) in the bottomdielectric portion of the coating under all silver based IR reflectinglayer(s) (e.g., see FIGS. 1(b)-1(i)), and/or (ii) in a middle dielectricportion of the coating between a pair of silver based IR reflectinglayers (e.g., see FIGS. 1(e)-1(i)).

As explained above and shown in the figures, the coated article mayinclude a dielectric layer(s) 2, 2″ (e.g., ZrO₂ or SiZrO_(x)) as shownin FIGS. 1(b)-(i), which may possibly be located under and directlycontacting the first crystalline or substantially crystalline layer 3comprising zinc oxide doped with from about 1-30% Sn, and/or below azinc oxide inclusive layer 3″. The dielectric layer(s) 2 (and 2″) may beof or include silicon oxide optionally doped with Al, zirconium oxide(e.g., ZrO₂), zirconium oxynitride, silicon zirconium oxide and/orsilicon zirconium oxynitride (e.g., SiZrO_(x), ZrO₂, SiO₂, and/orSiZrO_(x)N_(y)). The dielectric layer 2 (or 2″) may be in direct contactwith the glass substrate 1 (e.g., see FIGS. 1(b), 1(e), 1(g), 1(h)). Thedielectric layer(s) 2, 2″ may each have a physical thickness of fromabout 10-600 Å, more preferably from about 40-400 Å, more preferablyfrom about 50-300 Å, and most preferably from about 50-200 Å, or fromabout 40-170 or 80-140 Å. The dielectric layer(s) 2, 2″ is/arepreferably an oxide based dielectric layer, and preferably containslittle or no nitrogen. For example, the dielectric layer(s) 2, 2″ mayeach comprise from 0-20% nitrogen, more preferably from 0-10% nitrogen,and most preferably from 0-5% nitrogen (atomic %).

The FIG. 1(i) embodiment is based on the embodiments of FIGS. 1(a)-(b),1(e), and 1(h) discussed herein, and layer and performance descriptionsregarding those embodiments also apply to FIG. 1(i). However, the FIG.1(i) embodiment also includes an absorber film made up of layers 57 and59, where the absorber film is provided in the central portion of thelayer stack and over dielectric layers 11, 2″ and 3″ as describedherein. Layer 3″ may be zinc stannate, zinc oxide, zinc aluminum oxide,or dope zinc oxide as discussed above in different embodiments of thisinvention. Layer 2″ is discussed above, and may be of or include siliconoxide optionally doped with Al, zirconium oxide (e.g., ZrO₂), siliconzirconium oxide and/or silicon zirconium oxynitride (e.g., SiZrO_(x),ZrO₂, SiO₂, and/or SiZrO_(x)N_(y)).

In the FIG. 1(i) embodiment, the absorber film may be a multi-layerabsorber film including a first layer 57 of or including silver (Ag),and a second layer 59 of or including NiCr which may be partially orfully oxided (NiCrO_(x)), and possibly slightly nitrided. Such amulti-layer absorber film 57, 59 may thus, in certain exampleembodiments, be made up of a layer sequence of Ag/NiCrO_(x). This layersequence may be repeated in certain example instances. For example, theabsorber film may be made up of a layer sequence ofAg/NiCrO_(x)/Ag/NiCrO_(x), or Ag/NiCrO_(x)/Ag/NiCrO_(x)/Ag/NiCrO_(x), incertain example embodiments of this invention, which each of the layersin the sequence contributing to the light absorption. Elements from onelayer may diffuse into an adjacent layer due to HT or other factors. TheNiCr based layer 59 of the absorber may be initially deposited inmetallic form, or as a suboxide, in certain example embodiments. Thesilver based layer 57 may be a continuous layer, and/or may optionallybe doped, in certain example embodiments. Examples 30-47 of exampleembodiments of this invention relate to at least the FIG. 1(i)embodiment (see FIGS. 47-56). Moreover, as explained herein, in certainexample embodiments, in certain example embodiments it has surprisinglyand unexpectedly been found that initially sputter-depositing thedielectric layer(s) 2 and/or 2″ of or including silicon oxide, zirconiumoxide, zirconium oxynitride, silicon zirconium oxide and/or siliconzirconium oxynitride (e.g., SiZrO_(x), ZrO₂, SiO₂, and/orSiZrO_(x)N_(y)) so as to comprise a monoclinic phase crystalline phase(see m-ZrO₂ peaks in the upper graph of FIG. 51) is advantageous in thatit results in improved thermal stability (lower ΔE* value) and/orreduced change in visible transmission (e.g., T_(vis) or TY) of thecoated article upon heat treatment (HT).

The silver based layer 57 of the absorber film is preferablysufficiently thin so that its primary function is to absorb visiblelight and provide desirable coloration (as opposed to being much thickerand primarily function as an IR reflection layer). The NiCr or NiCrO_(x)59 is provided over and contacting the silver 57 of the absorber film inorder to protect the silver, and also to contribute to absorption. Incertain example embodiments, the silver based layer 57 of the absorberfilm may be no more than about 30 Å thick, more preferably no greaterthan about 20 Å thick, and most preferably no greater than about 15 Åthick, and possibly no greater than about 12 Å thick, in certain exampleembodiments of this invention. In certain example embodiments, the NiCrbased layer 59 of the absorber film may be from about 5-200 Å thick,more preferably from about 10-110 Å thick, and most preferably fromabout 40-90 Å thick. In certain example embodiments, the ratio ofAg/NiCrO_(x) in the absorber film may be 1:Z (where 0.1<Z<20, morepreferably where 2<Z<15, and most preferably where 3<Z<12), with anexample being about 1:5.

With respect to the silver based layer 57 of the absorber film beingsufficiently thin so that its primary function is to absorb visiblelight and provide desirable coloration (as opposed to being much thickerand primarily function as an IR reflection layer), the ratio of thephysical thickness of the IR reflecting layer 7 (e.g., silver) to thephysical thickness of the silver based layer 57 is preferably at least5:1, more preferably at least about 8:1, even more preferably at leastabout 10:1, and even more preferably at least about 15:1. Likewise, theratio of the physical thickness of the IR reflecting layer 19 (e.g.,silver) to the physical thickness of the silver based layer 57 ispreferably at least 5:1, more preferably at least about 8:1, even morepreferably at least about 10:1, and even more preferably at least about15:1.

While a single layer of NiCr (or other suitable material) may also beused as an absorber film in low-E coatings in certain exampleembodiments of this invention (e.g., see absorber film 42 in FIGS. 1(d)and 1(f)), it has surprisingly been found that using silver 57 in anabsorber film (single layer, or multi-layer, absorber film) of FIG. 1(i)provides for several unexpected advantages compared to a single layer ofNiCr as the absorber. First, it has been found that a single layer ofNiCr as the absorber tends to cause yellowish coloration in certainlow-E coating coated articles, which may not be desirable in certaininstances. In contrast, it has been surprisingly found that using silver57 in an absorber films tends to avoid such yellowish coloration and/orinstead provide for more desirable neutral coloration of the resultingcoated article. Thus, the use of silver 57 in an absorber film has beenfound to provide for improved optical characteristics. Second, the useof a single layer of NiCr 42 as the absorber tends to also involveproviding silicon nitride based layers on both sides of the NiCr so asto directly sandwich and contact the NiCr therebetween. For example, seeFIGS. 1(d) and 1(f). It has been found that the provision of siliconnitride in certain locations in a coating stack may lead to compromisedthermal stability upon HT. In contrast, it has been surprisingly foundthat when using silver in an absorber film as shown in FIG. 1(i) forexample, a pair of immediately adjacent silicon nitride layers are notneeded, so that thermal stability upon HT may be improved. Thus, the useof silver 57 in an absorber film has been found to provide for improvedthermal stability including lower ΔE* values and therefor improvedmatchability between HT and non-HT versions of the same coating. The useof silver in an absorber film may also provide for improvedmanufacturability in certain situations.

While the absorber film 57, 59 in FIG. 1(i) is provided in the centralportion of the layer stack between the IR reflecting layers 7 and 19, itis also possible to provide such an absorber film 57, 59 instead in thelower portion of the layer stack below the bottom IR reflecting layer 7,or in another suitable location. For example, the FIG. 1(i) embodimentmay be modified by moving directly adjacent and contacting layers 57 and59 to a position between layers 2 and 3, so that layers 2 and 57 contacteach other, and layers 59 and 3 contact each other. As another example,the FIG. 1(i) embodiment may be modified by moving the sequence of threelayers 3″/57/59 from the central portion of the stack to a positionbetween layers 2 and 3 in FIG. 1(i), so that layers 2 and 3″ contacteach other, and layers 59 and 3 contact each other. However, it has beensurprisingly found that by providing the absorber film 57, 59 in thecentral portion of the layer stack as shown in FIG. 1(i), opticalcharacteristics such as SHGC and glass side reflectance may be improved.

FIG. 1(i) illustrates layer 59 of the absorber film as of or includingNiCrO_(x) (partially or fully oxided). However, layer 59 of the absorberfilm may be of or include other metal based materials (e.g., NiCr, Ni,Cr, NiCrO_(x), NiCrN_(x), NiCrON, NiCrM, NiCrMoO_(x), Ti, or othersuitable material).

It is noted that zinc stannate layers 11 and/or 23 may be replaced withrespective layer(s) of other material(s) such as tin oxide, zinc oxide,zinc oxide doped with from 1-20% Sn (as discussed elsewhere hereinregarding layers 3, 3″, 13), or the like, in any embodiment herein.

While various thicknesses and materials may be used in layers indifferent embodiments of this invention, example thicknesses andmaterials for the respective layers on the glass substrate 1 in the FIG.1(i) embodiment are as follows, from the glass substrate outwardly:

TABLE 1′ Example Materials/Thicknesses; FIG. 1(i) Embodiment PreferredRange More Preferred Example Layer Glass ({acute over (Å)}) ({acute over(Å)}) (Å) ZrO_(x)/SiZrO_(x) (layer 2) 10-600 {acute over (Å)} 10-400{acute over (Å)} 80-140 Å Sn-doped ZnO 20-900 (or 100-550 {acute over(Å)} 223 Å (layer 3) 100-900) {acute over (Å)} Ag (layer 7) 60-260{acute over (Å)} 100-170 {acute over (Å)} 151 Å NiCrO_(x) (layer 9)10-100 {acute over (Å)} 20-45 {acute over (Å)} 41 Å ZnSnO (layer 11)100-1200 Å 150-500 Å 280 Å ZrO_(x)/SiZrO_(x) (layer 2″) 10-600 {acuteover (Å)} 10-400 {acute over (Å)} 80-140 Å Sn-doped ZnO 20-900 {acuteover (Å)} 50-150 {acute over (Å)} 100 Å (layer 3″) Ag (layer 57) 3-30{acute over (Å)} 4-20 {acute over (Å)} 5-15 Å NiCrO_(x) (layer 59) 5-200{acute over (Å)} 10-110 {acute over (Å)} 40-90 Å Sn-doped ZnO 60-900{acute over (Å)} 120-400 {acute over (Å)} 331 Å (layer 13) Ag (layer 19)80-280 {acute over (Å)} 120-250 {acute over (Å)} 156 Å NiCrO_(x) (layer21) 10-100 {acute over (Å)} 20-45 {acute over (Å)} 41 Å ZnSnO (layer 23)10-750 Å 70-200 Å 103 Å Si₃N₄ (layer 25) 10-750 {acute over (Å)} 100-240{acute over (Å)} 214 Å

In certain embodiments of this invention, layer systems herein (e.g.,see FIGS. 1(a)-(i)) provided on clear monolithic glass substrates (e.g.,6 mm thick glass substrates for example reference purposes) have coloras follows before heat treatment, as viewed from the glass side of thecoated article (R_(G) %) (Ill. C, 2 degree Observer):

TABLE 2 Reflection/Color (R_(G)) Before and/or After Heat TreatmentGeneral Preferred R_(g)Y (%) 5-35%, or 5-20% 8-18% a_(g)* −5.0 to +4.0 −3.5 to +2.0 b_(g)* −16.0 to 0.0  −14.0 to −5.0

Comparative Examples 1 and 2

FIG. 19 is a cross sectional view of a first Comparative Example (CE)coated article, and FIG. 23 is an XRD Lin (Cps) vs. 2-Theta-Scale graphillustrating, for the first Comparative Example (CE), the relative large166% change in Ag (111) peak height due to heat treatment.

A difference between the first Comparative Example coating (see FIG.19), and Examples 1-24, 27-28, and 30-33 below, is that the lowermostdielectric stack of the coating in the first Comparative Example is madeup of a Zn₂SnO₄ layer, and a zinc oxide based layer that is doped withaluminum. The metal content of the zinc stannate layer (Zn₂SnO₄ is aform of zinc stannate) is about 50% Zn and about 50% Sn (wt. %); andthus the zinc stannate layer is sputter-deposited in amorphous form. Theoverall thickness of the lowermost dielectric stack in the first CE wasabout 400-500 angstroms, with the zinc stannate layer making up themajority of that thickness. FIG. 23 illustrates, for the firstComparative Example (CE), the relative large 166% change in Ag (111)peak height due to heat treatment at about 650 degrees C. which isindicative of a significant change in structure of the silver layersduring the heat treatment, and which is consistent with the ΔE* valuesover 4.0 realized by the Comparative Example. Thus, the first CE wasundesirable because of the significant changes in the Ag (111) peak, andthe high of ΔE* values over 4.0, due to heat treatment. In contrast withthe first Comparative Example, Examples 1-24, 27-28, and 30-33 below hada crystalline or substantially crystalline layer 3, 13 with a metalcontent of either 90(Zn)/10(Sn) or 85(Zn)/15(Sn) directly under andcontacting silver 7, 19, and realized significantly improved/lower ΔE*values.

A second Comparative Example (CE 2) is shown in FIGS. 34-35. FIG. 34 ischart illustrating sputter-deposition conditions for thesputter-deposition of the low-E coating of Comparative Example 2 (CE 2)on a 6 mm thick glass substrate. The layer stack of CE 2 is the same asthat shown in FIG. 1(b) of the instant application, except that thelowermost dielectric layer in CE 2 is made of silicon nitride (dopedwith about 8% aluminum) instead of the SiZrO_(x) shown in FIG. 1(b).Thus, the bottom dielectric stack in CE 2 is made up of only thissilicon nitride based layer and a zinc oxide layer 3 doped with about10% Sn. The thicknesses of the layers of the coating of CE 2 are in thefar right column of FIG. 34. For example, the bottom silicon nitridebased layer, doped with Al (sputtered from an SiAl target in anatmosphere of Ar and N₂ gas), is 10.5 nm thick in CE 2, the zinc oxidelayer 3 doped with about 10% Sn directly under the bottom silver is 32.6nm thick in CE 2, and so forth.

It can be seen in FIG. 35 that CE 2 suffers from relatively high glassside reflective ΔE* values (ΔE*R_(g)) and film side reflective ΔE*values (ΔE*R_(f)) over 4.0, due to heat treatments of 12, 16, and 24minutes. For example, FIG. 35 shows that CE has a relatively high glassside reflective ΔE* value (ΔE*R_(g)) of 4.9 and a relatively high filmside reflective ΔE* value (ΔE*R_(f)) of 5.5 due to heat treatment for 12minutes. FIG. 35 is a chart illustrating optical characteristics ofComparative Example 2 (CE 2): as coated (annealed) before heat treatmentin the left-most data column, after 12 minutes of heat treatment at 650degrees C. (HT), after 16 minutes of HT at 650 degrees C. (HTX), andafter 24 minutes of heat treatment at 650 degrees C. (HTXXX) in the farright data column. These relatively high ΔE* values of CE 2 areundesirable.

Accordingly, Comparative Example 2 (CE 2) in FIGS. 34-35 demonstratesthat undesirably high ΔE* values are realized, even when a crystallineor substantially crystalline zinc oxide layer 3 doped with about 10% Snis provided directly below the bottom silver layer 7, when the onlylayer between that layer 3 and the glass substrate 1 is a siliconnitride based layer. The difference between the CE 2 coating, andExamples 1-24, 27-28, and 30-33 below, is that Examples 1-24, 27-28, and30-33 below were surprisingly and unexpectedly able to realize muchimproved (lower) ΔE* values using the crystalline or substantiallycrystalline zinc oxide layer 3 doped with about 10% or 15% Sn, by nothaving a silicon nitride based layer located directly below andcontacting the crystalline or substantially crystalline zinc oxide layer3 doped with about 10% or 15% Sn.

Examples 11-14, 19-21, and 26-33 below also demonstrate that replacingthe bottom silicon nitride based layer of CE 2 with a SiZrO_(x) or ZrO₂layer 2 dramatically improves/lowers ΔE* values in an unexpected manner.

Examples 1-48

Surprisingly and unexpectedly, it was found that when the lowermostdielectric stack 5, 6 of the Comparative Example (CE) (made up mostly bythe zinc stannate layer which is amorphous as deposited) in FIG. 19 wasreplaced with a crystalline or substantially crystalline Sn-doped zincoxide layer 3 of similar thickness (the rest of the stack remainedsubstantially the same) contacting the silver based layer, with nosilicon nitride based layer directly under and contacting thecrystalline or substantially crystalline layer 3, the result was a muchmore thermally stable product with significant lower ΔE* values and amuch smaller change in Ag (111) peak height due to heat treatment atabout 650 degrees C. The metal content of the crystalline orsubstantially crystalline Sn-doped zinc oxide layer 3 in Examples 1-24,27-28, and 30-48 was approximately 90% Zn and 10% Sn (wt. %) (see also85% Zn, and 15% Sn metal content for “85” regarding layer 13 in Example19), which helped allow the Sn-doped zinc oxide layers 3, 13 in Examples1-24, 27-28, 30-48 to be sputter-deposited in crystalline orsubstantially crystalline form (as opposed to the amorphous form in theCE). For instance, FIG. 20 illustrates the layer stack of Example 10,FIG. 21 illustrates the sputter-deposition conditions and layerthicknesses of Example 10, and FIG. 22 illustrates the much smaller 66%change in Ag (111) peak height due to heat treatment at about 650degrees C. for Example 10 which is consistent with the much lower ΔE*values realized by Examples 1-24, 27-28 and 30-33. FIG. 16 alsoillustrates the relatively small refractive index (n) shift, upon heattreatment, for Example 8.

The Example coated articles (each annealed and heat treated), Examples1-48, were made in accordance with certain example embodiments of thisinvention. Indicated example coatings 30 were sputter-deposited via thesputtering conditions (e.g., gas flows, voltage, and power), sputteringtargets, and to the layer thicknesses (nm) shown in FIGS. 2, 3, 6, 7, 9,11, 13, 15, 21, 24-26, 28, 30, 32, and 36-57. For example, FIG. 2 showsthe sputtering conditions, sputtering targets used forsputter-depositing, and the layer thicknesses for the coating of Example1, FIG. 3 shows the sputtering conditions, sputtering targets used forsputter-depositing, and the layer thicknesses for the coating of Example2, FIG. 6 shows the sputtering conditions, sputtering targets used forsputter-depositing, and the layer thicknesses for the coating of Example3, FIG. 7 shows the sputtering conditions, sputtering targets used forsputter-depositing, and the layer thicknesses for the coating of Example4, and so forth. Meanwhile, data for the indicated Examples, includingvisible transmission (TY or T_(vis)), glass side visible reflectance(R_(g)Y or RGY), film side visible reflectance (R_(f)Y or RFY), a* andb* color values, L* values, and sheet resistance (SR or R_(s)) are shownin FIGS. 4, 5, 8, 10, 12, 14, 18, 27, 29, 31, 33, and 36-56. Asexplained above, ΔE* values are calculated using the L*, a*, and b*values, taken before and after heat treatment, for a given example. Forinstance, a glass side reflective ΔE* value (ΔE*_(G) or ΔE*R_(g)) iscalculated using the glass side reflective L*, a*, and b* values, takenbefore and after heat treatment, for a given example. As anotherexample, a film side reflective ΔE* value (ΔE*_(F) or ΔE*R_(f)) iscalculated using the glass side reflective L*, a*, and b* values, takenbefore and after heat treatment, for a given example. As anotherexample, a transmissive ΔE* value (ΔE*_(T)) is calculated using theglass side reflective L*, a*, and b* values, taken before and after heattreatment, for a given example.

For examples having approximately 3 mm thick glass substrates, in FIGS.4, 5, 8, 10, 12, 14, and 18, “HT” refers to heat treatment at 650degrees for about 8 minutes, “HTX” refers to heat treatment at 650degrees for about 12 minutes, and “HTXXX” refers to heat treatment at650 degrees for about 20 minutes. And for examples having approximately6 mm thick glass substrates, in FIGS. 4, 5, 8, 10, 12, 14, 18, 27, 29,31, 33, and 36-56 “HT” refers to heat treatment at 650 degrees for about12 minutes, “HTX” refers to heat treatment at 650 degrees for about 16minutes, and “HTXXX” refers to heat treatment at 650 degrees for about24 minutes. The heat treatment temperatures and times are for referencepurposes only (e.g., to simulate examples of different tempering and/orheat bending processes).

FIGS. 4 and 5, for instance, illustrate the ΔE* values for Examples 1and 2, respectively. The data for Example 1 is explained below indetail, for purposes of example and explanation, and that discussionalso applies to the data for Examples 2-33.

As shown in FIG. 4, Example 1 as coated (prior to heat treatment) had avisible transmission (TY or T_(vis)) of 74.7%, a transmissive L* valueof 89.3, a transmissive a* color value of −4.7, a transmissive b* colorvalue of 5.8, a glass side reflectance (R_(g)Y) of 9.6%, a glass sidereflective L* value of 37.1, a glass side reflective a* color value of−1.1, a glass side reflective b* color value of −10.1, a film sidereflectance (R_(f)Y) of 9.9%, a film side reflective L* value of 37.7, afilm side reflective a* color value of −1.5, a film side reflective b*color value of −5.7, and a sheet resistance (SR) of 2.09 ohms/square.FIG. 2 shows the thicknesses of the layers in Example 1. In particular,FIG. 2 shows that the layer thicknesses for Example 1 were are follows:glass/crystalline Sn-doped ZnO(47.0 nm)/Ag(15.1 nm)/NiCrO_(x) (4.1nm)/amorphous zinc stannate(73.6 nm)/crystalline Sn-doped ZnO(17.7nm)/Ag(23.2 nm)/NiCrO_(x) (4.1 nm)/amorphous zinc stannate(10.8nm)/silicon nitride doped with aluminum (19.1 nm).

The coated article of Example 1, which had a 6 mm thick glass substrate1, was then heat treated. As shown in FIG. 4, Example 1 following heattreatment at 650 degrees C. for about 12 minutes had a visibletransmission (TY or T_(vis)) of 77.0%, a transmissive L* value of 90.3,a transmissive a* color value of −3.5, a transmissive b* color value of4.9, a glass side reflectance (R_(g)Y) of 9.8%, a glass side reflectiveL* value of 37.5, a glass side reflective a* color value of −0.7, aglass side reflective b* color value of −10.5, a film side reflectance(R_(f)Y) of 10.2%, a film side reflective L* value of 38.1, a film sidereflective a* color value of −1.4, a film side reflective b* color valueof −8.0, a sheet resistance (SR) of 1.75, a transmissive ΔE* value of1.8, a glass side reflective ΔE* value 0.7, and a film side reflectiveΔE* value of 2.4.

It will be appreciated that these ΔE* values for Example 1 (and alsothose for Examples 2-48) are much improved (significantly lower) thanthose of the prior art discussed in the background and compared to thevalues over 4.0 for the Comparative Examples (CEs) discussed above.Thus, the data from the examples demonstrates, for example, that whenthe lowermost dielectric stacks of the Comparative Examples was replacedwith at least a crystalline or substantially crystalline Sn-doped zincoxide layer of similar thickness (the rest of the stack remainedsubstantially the same), with no silicon nitride based layer directlyunder and contacting the crystalline or substantially crystallineSn-doped zinc oxide layer 3, the result was a much more thermally stableproduct with significant lower ΔE* values and a much smaller change inAg (111) peak height due to heat treatment.

Other examples show these same unexpected results, compared to theComparative Example. In general, the Examples demonstrate that thecrystalline or substantially crystalline Sn-doped zinc oxide layer,and/or the layer(s) 2, 2″ of or including SiZrO_(x), ZrO_(x), SiO₂,significantly improved ΔE* values. For example, Examples 1-10 had layerstacks generally shown by FIG. 1(a) where the only dielectric layerbeneath the bottom silver was the crystalline or substantiallycrystalline Sn-doped zinc oxide layer 3 with a metal content ofapproximately 90% Zn and 10% Sn (wt. %). In Examples 11-14, 19-24, 27-28metal content of the crystalline or substantially crystalline Sn-dopedzinc oxide layer 3 was approximately 90% Zn and 10% Sn (wt. %), directlyover a SiZrO_(x) layer 2 where metal content of the layer 2 was about85% Si and 15% Zr (atomic %). In Examples 30-48 the crystalline orsubstantially crystalline Sn-doped zinc oxide layer 3 was approximately90% Zn and 10% Sn (wt. %), and provided directly over a ZrO₂ layer 2 asshown in FIGS. 1(i) and 52. In Examples 15-16 metal content of thecrystalline or substantially crystalline Sn-doped zinc oxide layer 3 wasapproximately 90% Zn and 10% Sn (wt. %), directly over a ZrO₂ layer 2;and in Examples 17-18 metal content of the crystalline or substantiallycrystalline Sn-doped zinc oxide layer 3 was approximately 90% Zn and 10%Sn (wt. %), directly over a SiO₂ layer 2 doped with about 8% Al (atomic%). These examples surprisingly and unexpectedly realized much improvedΔE* values compared to the Comparative Examples 1-2.

The layer stacks of Examples 1-10 are generally illustrated by FIG.1(a). The layer stacks of Examples 11-14, 19 and 27 are generallyillustrated by FIG. 1(b), with layer 2 being of SiZrO_(x). The layerstacks of Examples 15-16 are generally illustrated by FIG. 1(b), withlayer 2 being of ZrO₂. The layer stacks of Examples 17-18 are generallyillustrated by FIG. 1(b), with layer 2 being of SiO₂. The layer stacksof Examples 20-21 and 28 are generally illustrated by FIG. 1(e), withlayers 2 and 2″ being of SiZrO_(x). The layer stacks of Examples 23-24are generally illustrated by FIG. 1(f), with layers 2 and 2″ being ofSiZrO_(x). The layer stack of Example 25 is generally illustrated byFIG. 1(g), with layers 2 and 2″ being of SiZrO_(x). The layer stack ofExample 22 is generally illustrated by FIG. 1(d), with layer 2 being ofSiZrO_(x). The layer stack of Example 26 is generally illustrated byFIG. 1(h), with layers 2 and 2″ being of SiZrO_(x), oxide layer 3′havinga meal content 90% Zn and 10% Sn, and oxide layers 3, 13 being zincoxide doped with about 4-8% Al. The layer stack of Example 29 isgenerally illustrated by FIG. 1(h), except that layer 2″ is not presentin Example 29, and with layer 2 being of SiZrO_(x), oxide layer 3′havinga metal content 90% Zn and 10% Sn, and oxide layers 3, 13 being zincoxide doped with about 4-8% Al. The layer stacks of Examples 30-48 aregenerally illustrated by FIGS. 1(i) and 52, with layers 2 and 2″ beingof ZrO₂. These examples surprisingly and unexpectedly realized muchimproved ΔE* values compared to the Comparative Examples 1-2. Theseexamples demonstrate that the crystalline or substantially crystallineSn-doped zinc oxide layer(s) (e.g., layer 3 and/or 13), and/or thedielectric layer(s) 2, 2″ of or including SiZrO_(x), ZrO_(x), SiO₂,significantly improved/lowered ΔE* values.

For instance, comparing Examples 23-24 (SiZrO_(x) layer 2″ added to thecenter dielectric portion of the coating as shown in FIG. 1(f)) toExample 22 (no such layer 2″ in the center dielectric portion as shownin FIG. 1(d)) demonstrates and evidences that the addition of theSiZrO_(x) layer 2″ in Examples 23-24 unexpectedly improved/lowered atleast glass side reflective ΔE* values. Thus, it will be appreciatedthat the addition of the SiZrO_(x) layer 2″ provides for unexpectedresults.

Furthermore, comparing Example 28 (SiZrO_(x) layer 2″ added to thecenter dielectric portion of the coating as shown in FIG. 1(e)) toExample 27 (no such layer 2″ in the center dielectric portion as shownin FIG. 1(b)) further demonstrates and evidences that the addition ofthe SiZrO_(x) layer 2″ in Example 28 unexpectedly improved/lowered glassside reflective ΔE* values. Thus, it will again be appreciated that theaddition of the SiZrO_(x) or ZrO₂ layer 2″ provides for unexpectedresults with respect to improving thermal stability. Examples 30-48 aregenerally illustrated by FIGS. 1(i) and 52 including absorber film 57,59, with layers 2 and 2″ being of ZrO₂ in these examples. These examplessurprisingly and unexpectedly realized much improved ΔE* values comparedto the Comparative Examples 1-2. Examples 30-48 demonstrate that thecrystalline or substantially crystalline Sn-doped zinc oxide layer(s)(e.g., layer 3 and/or 13), and the dielectric layer(s) 2, 2″ of orincluding ZrO₂, significantly improved/lowered ΔE* values in anunexpected manner Examples 30-48 further demonstrate that providing theabsorber film including silver inclusive layer 57 and NiCrO_(x)inclusive layer 59 allows the visible transmission to be tuned to adesirable value without sacrificing thermal stability or desired colorof the resulting coated article. For example, Examples 30-48 with theAg/NiCrO_(x) absorber film (57, 59) as shown in FIG. 1(i) havesurprisingly more neutral glass side reflective b* values (Rg b*, orR-out b*) values compared to Examples 23-24 where the single NiCr layerabsorber was utilized.

Comparing Examples 34-42 and 48, to Comparative Examples (CEs) 43-47, itcan be seen that it has surprisingly and unexpectedly been found thatinitially sputter-depositing the dielectric layer(s) 2 and/or 2″ of orincluding silicon oxide, zirconium oxide, zirconium oxynitride, siliconzirconium oxide and/or silicon zirconium oxynitride (e.g., SiZrO_(x),ZrO₂, SiO₂, and/or SiZrO_(x)N_(y)) so as to comprise a monoclinic phasecrystalline structure in Examples 34-42 and 48 is advantageous in thatit results in improved thermal stability (lower ΔE* value) and/orreduced change in visible transmission (e.g., T_(vis) or TY) of thecoated article upon heat treatment (HT). Generally speaking, CEs 43-47,which may still be according to certain example embodiments of thisinvention, had less preferred (higher) ΔE* values due to nonmonoclinicZrO₂ layers 2, 2″, compared to Examples 34-42 and 48 which hadmonoclinic ZrO₂ layers 2, 2″ and thus improved/lower ΔE* values. Incertain example embodiments, in connection with certain sputteringequipment, the monoclinic phase (e.g., see the m-ZrO₂ peaks in the uppergraph of FIG. 51) for the dielectric layer (e.g., ZrO₂) 2 and/or 2″ maybe achieved by using a high oxygen gas flow for that layer during thesputter-deposition process of that layer, and using a metallicsputtering target (e.g., metal Zr or SiZr target) (e.g., see FIG. 55),as in Examples 34-42. In this respect, FIG. 51 illustrates graphs forsputter-depositing a ZrO₂ layer using a metal Zr target (upper graph)and a ceramic ZrO_(x) target (lower graph), before and after HT, andshows that the layer comprises a monoclinic phase (see the peak atm-ZrO₂) when the metal target with high gas flow (e.g., see FIG. 55) wasused, but not when the ceramic target was used in certain situations. Itis noted, however, that it has been found that monoclinic phase forlayer 2 and/or 2″ may indeed be achieved when the sputter-depositinguses a ceramic target such as in Example 48, with low or high oxygen gasflows, depending upon the type of sputtering equipment used.

FIG. 52 (see also FIG. 1(i)) is a cross sectional view of coatedarticles according to Examples 34-42, 48 and Comparative Examples (CEs)43-47. FIG. 53 illustrates the optical data of Examples 34-42 as coated(AC; annealed) before heat treatment in the left-most data column ofeach example, and after 12 minutes of heat treatment at 650 degrees C.(HT) in the right data column of each example, Examples 34-42 having acoating stack as shown in FIG. 1(i) and FIG. 52 with monoclinic ZrO₂layers 2 and 2″ deposited with metal Zr target, and layer thicknessesfor Examples 34-42 as shown in FIG. 55; where sample 7982 is Example 34,sample 8077 is Example 35, sample 8085 is Example 36, sample 8090 isExample 37, sample 8091 is Example 38, sample 8097 is Example 39, sample8186 is Example 40, sample 8187 is Example 41, and sample 8202 isExample 42.

FIG. 55 is a chart illustrating deposition process conditions and layerthicknesses for Example 37 having monoclinic ZrO₂ layers, with totaloxygen flow (ml) during the sputtering process for each layer indicatedby the sum of O₂ setpoint, O₂ tune, and O₂ offset, with the high oxygengas flow during sputter-deposition of the ZrO₂ layers helping providethe monoclinic phase of the ZrO₂ layers 2 and 2″ of Example 37(monoclinic Examples 34-36 and 38-42 had similar process conditions). Inthe FIG. 52 and FIG. 1(i) embodiments, it is noted, for example, thatthe center ZrO₂ layer 2″ may be omitted in certain example instances.

FIG. 57 is a chart illustrating deposition process conditions and layerthicknesses for Example 48 having monoclinic ZrO₂ layer 2 (layer 2″ wasomitted), where the ZrO layer 2 having monoclinic phase wassputter-deposited using a ceramic ZrO_(x) target. The layer stack ofExample 48 is shown in FIGS. 1(i) and 52 (with layer 2″ omitted), andthe respective layer thicknesses are provided in FIG. 57. FIG. 58illustrates the ΔE* values for coatings according to Example 48 aftervarious heat treatment times, and FIG. 59 illustrates optical data andsheet resistance data for the coatings according to Example 48.

FIG. 54 illustrates the optical data of Comparative Examples (CEs) 43-47as coated (AC; annealed) before heat treatment in the left-most datacolumn of each example, and after 12 minutes of heat treatment at 650degrees C. (HT) in the right data column of each example, Examples 43-47having a coating stack as shown in FIG. 1(i) and FIG. 52 withnon-monoclinic ZrO₂ layers deposited with ceramic target, and layerthicknesses for Examples 43-47 as shown in FIG. 56; where sample 8392 isCE 43, sample 8394 is CE 44, sample 8395 is CE 45, sample 8396 is CE 46,and sample 8397 is CE 47. FIG. 56 is a chart illustrating depositionprocess conditions and layer thicknesses for Comparative Example (CE) 44having nonmonoclinic ZrO₂ layers 2 and 2″, with total oxygen flow (ml)during the sputtering process for each layer indicated by the sum of O₂setpoint, O₂ tune, and O₂ offset, with the low oxygen gas flow duringsputter-deposition of the ZrO₂ layers together with ceramic ZrO_(x)target helping provide the non-monoclinic phase of the ZrO₂ layers ofExample 44 (nonmonoclinic Examples 43 and 45-47 had similar processconditions).

Comparing Examples 34-42, 48 to Comparative Examples (CEs) 43-47, it canbe seen that Examples 34-42, 48 with the monoclinic ZrO₂ layers 2 and 2″as-deposited realized lower/better ΔE* values, and thus improved thermalstability and color matching upon HT, than did Examples 43-47 which hadnonmonoclinic phase ZrO₂ layers 2 and 2″.

Certain terms are prevalently used in the glass coating art,particularly when defining the properties and solar managementcharacteristics of coated glass. Such terms are used herein inaccordance with their well known meaning. For example, as used herein:

Intensity of reflected visible wavelength light, i.e. “reflectance” isdefined by its percentage and is reported as R_(x)Y or R_(x) (i.e. the Yvalue cited below in ASTM E-308-85), wherein “X” is either “G” for glassside or “F” for film side. “Glass side” (e.g. “G” or “g”) means, asviewed from the side of the glass substrate opposite that on which thecoating resides, while “film side” (i.e. “F” or “f”) means, as viewedfrom the side of the glass substrate on which the coating resides.

Color characteristics are measured and reported herein using the CIE LABa*, b* coordinates and scale (i.e. the CIE a*b* diagram, Ill. CIE-C, 2degree observer). Other similar coordinates may be equivalently usedsuch as by the subscript “h” to signify the conventional use of theHunter Lab Scale, or Ill. CIE-C, 10° observer, or the CIE LUV u*v*coordinates. These scales are defined herein according to ASTM D-2244-93“Standard Test Method for Calculation of Color Differences FromInstrumentally Measured Color Coordinates” Sep. 15, 1993 as augmented byASTM E-308-85, Annual Book of ASTM Standards, Vol. 06.01 “StandardMethod for Computing the Colors of Objects by 10 Using the CIE System”and/or as reported in IES LIGHTING HANDBOOK 1981 Reference Volume.

Visible transmittance can be measured using known, conventionaltechniques. For example, by using a spectrophotometer, such as a PerkinElmer Lambda 900 or Hitachi U4001, a spectral curve of transmission isobtained. Visible transmission is then calculated using the aforesaidASTM 308/2244-93 methodology. A lesser number of wavelength points maybe employed than prescribed, if desired. Another technique for measuringvisible transmittance is to employ a spectrometer such as a commerciallyavailable Spectrogard spectrophotometer manufactured by PacificScientific Corporation. This device measures and reports visibletransmittance directly. As reported and measured herein, visibletransmittance (i.e. the Y value in the CIE tristimulus system, ASTME-308-85), as well as the a*, b*, and L* values, and glass/film sidereflectance values, herein use the Ill. C.,2 degree observer standard.

Another term employed herein is “sheet resistance”. Sheet resistance(R_(s)) is a well known term in the art and is used herein in accordancewith its well known meaning. It is here reported in ohms per squareunits. Generally speaking, this term refers to the resistance in ohmsfor any square of a layer system on a glass substrate to an electriccurrent passed through the layer system. Sheet resistance is anindication of how well the layer or layer system is reflecting infraredenergy, and is thus often used along with emittance as a measure of thischaracteristic. “Sheet resistance” may for example be convenientlymeasured by using a 4-point probe ohmmeter, such as a dispensable4-point resistivity probe with a Magnetron Instruments Corp. head, ModelM-800 produced by Signatone Corp. of Santa Clara, Calif.

The terms “heat treatment” and “heat treating” as used herein meanheating the article to a temperature sufficient to achieve thermaltempering, heat bending, and/or heat strengthening of the glassinclusive coated article. This definition includes, for example, heatinga coated article in an oven or furnace at a temperature of least about580 degrees C., more preferably at least about 600 degrees C., including650 degrees C., for a sufficient period to allow tempering, bending,and/or heat strengthening. In certain instances, the heat treatment maybe for at least about 8 minutes or more as discussed herein.

In an example embodiment of this invention, there is provided a coatedarticle including a coating on a glass substrate, wherein the coatingcomprises: a first crystalline or substantially crystalline layercomprising zinc oxide doped with from about 1-30% Sn (wt. %), providedon the glass substrate; a first infrared (IR) reflecting layercomprising silver located on the glass substrate and directly over andcontacting the first crystalline or substantially crystalline layercomprising zinc oxide doped with from about 1-30% Sn; wherein no siliconnitride based layer is located directly under and contacting the firstcrystalline or substantially crystalline layer comprising zinc oxidedoped with from about 1-30% Sn; at least one dielectric layer havingmonoclinic phase and comprising an oxide of zirconium (e.g., ZrO₂), andoptionally further including other element(s) such as Si; wherein the atleast one dielectric layer comprising the oxide of zirconium is located:(1) between at least the glass substrate and the first crystalline orsubstantially crystalline layer comprising zinc oxide doped with fromabout 1-30% Sn (wt. %), and/or (2) between at least the first IRreflecting layer comprising silver and a second IR reflecting layercomprising silver of the coating; optionally an absorber film includinga layer comprising silver, wherein a ratio of a physical thickness ofthe first IR reflecting layer comprising silver to a physical thicknessof the layer comprising silver of the absorber film is at least 5:1(more preferably at least 8:1, even more preferably at least 10:1, andmost preferably at least 15:1); and wherein the coated article isconfigured to have, measured monolithically, at least two of: (i) atransmissive ΔE* value of no greater than 3.0 due to a reference heattreatment for 12 minutes at a temperature of about 650 degrees C., (ii)a glass side reflective ΔE* value of no greater than 3.0 due to thereference heat treatment for 12 minutes at a temperature of about 650degrees C., and (iii) a film side reflective ΔE* value of no greaterthan 3.5 due to the reference heat treatment for 12 minutes at atemperature of about 650 degrees C.

The coated article of the immediately preceding paragraph may beconfigured to have, measured monolithically, all three of: (i) atransmissive ΔE* value of no greater than 3.0 due to a reference heattreatment for 12 minutes at a temperature of about 650 degrees C., (ii)a glass side reflective ΔE* value of no greater than 3.0 due to thereference heat treatment for 12 minutes at a temperature of about 650degrees C., and (iii) a film side reflective ΔE* value of no greaterthan 3.5 due to the reference heat treatment for 12 minutes at atemperature of about 650 degrees C.

In the coated article of any of the preceding two paragraphs, the leastone dielectric layer comprising the oxide of zirconium may be located atleast between at least the glass substrate and the first crystalline orsubstantially crystalline layer comprising zinc oxide doped with fromabout 1-30% Sn (wt. %).

In the coated article of any of the preceding three paragraphs, theleast one dielectric layer comprising the oxide of zirconium may belocated at least between at least the first IR reflecting layercomprising silver and the second IR reflecting layer comprising silverof the coating.

In the coated article of any of the preceding four paragraphs, the atleast one dielectric layer comprising the oxide of zirconium may includeboth a first layer comprising an oxide of zirconium, and a second layercomprising an oxide of zirconium (each of which may further includeadditional element(s) such as Si); wherein the first layer may belocated between at least the glass substrate and the first crystallineor substantially crystalline layer comprising zinc oxide doped with fromabout 1-30% Sn (wt. %); and wherein the second layer may be locatedbetween at least the first IR reflecting layer comprising silver and thesecond IR reflecting layer comprising silver of the coating.

In the coated article of any of the preceding five paragraphs, the atleast one dielectric layer may comprise or consist essentially of theoxide of zirconium and/or an oxide of silicon and zirconium (e.g.,SiZrO_(x)). For instance, the dielectric layer comprising the oxide ofsilicon and zirconium may have a metal content of from 51-99% Si andfrom 1-49% Zr, more preferably from 70-97% Si and from 3-30% Zr (atomic%).

In the coated article of any of the preceding six paragraphs, the atleast one dielectric layer may comprise ZrO₂.

In the coated article of any of the preceding seven paragraphs, thefirst crystalline or substantially crystalline layer comprising zincoxide may be doped with from about 1-20% Sn, more preferably from about5-15% Sn (wt. %).

In the coated article of any of the preceding eight paragraphs, thefirst crystalline or substantially crystalline layer comprising zincoxide doped with Sn may be crystalline or substantially crystalline assputter-deposited.

The coated article according to any of the preceding nine paragraphs maybe configured to have, measured monolithically, all of: (i) atransmissive ΔE* value of no greater than 2.5 due to a reference heattreatment for 12 minutes at a temperature of about 650 degrees C., (ii)a glass side reflective ΔE* value of no greater than 2.5 due to thereference heat treatment for 12 minutes at a temperature of about 650degrees C., and (iii) a film side reflective ΔE* value of no greaterthan 3.0 due to the reference heat treatment for 12 minutes at atemperature of about 650 degrees C.

The coated article according to any of the preceding ten paragraphs maybe configured to have, measured monolithically, at least two of: (i) atransmissive ΔE* value of no greater than 2.3 due to a reference heattreatment for 16 minutes at a temperature of about 650 degrees C., (ii)a glass side reflective ΔE* value of no greater than 2.0 due to thereference heat treatment for 16 minutes at a temperature of about 650degrees C., and (iii) a film side reflective ΔE* value of no greaterthan 3.0 due to the reference heat treatment for 16 minutes at atemperature of about 650 degrees C.

The coated article according to any of the preceding eleven paragraphsmay be configured so that the coating may have a sheet resistance(R_(s)) of no greater than 20 ohms/square, more preferably no greaterthan 10 ohms/square, and most preferably no greater than 2.5ohms/square.

The coated article according to any of the preceding twelve paragraphsmay have, measured monolithically, a visible transmission of at least35%, more preferably of at least 50%, and more preferably of at least68%.

In the coated article of any of the preceding thirteen paragraphs, thecoating as deposited may further comprise a first amorphous orsubstantially amorphous layer comprising zinc stannate located on theglass substrate over at least the first IR reflecting layer comprisingsilver. The first amorphous or substantially amorphous layer comprisingzinc stannate may have a metal content of from about 40-60% Zn and fromabout 40-60% Sn (wt. %).

In the coated article of any of the preceding fourteen paragraphs, thecoating may further comprise a contact layer located over and directlycontacting the first IR reflecting layer comprising silver. The contactlayer may comprise Ni and/or Cr, and may or may not be oxided and/ornitrided.

In the coated article of any of the preceding fifteen paragraphs, thecoating may further comprise: the second IR reflecting layer comprisingsilver located on the glass substrate over at least the first IRreflecting layer comprising silver, a second crystalline orsubstantially crystalline layer comprising zinc oxide doped with fromabout 1-30% Sn (wt. %), located under and directly contacting the secondIR reflecting layer comprising silver; and wherein no silicon nitridebased layer need be located between the glass substrate and the secondIR reflecting layer comprising silver.

In the coated article of any of the preceding sixteen paragraphs, thecoating may further comprise an amorphous or substantially amorphouslayer, as deposited, comprising zinc stannate located on the glasssubstrate over at least the second IR reflecting layer comprisingsilver. The amorphous or substantially amorphous layer comprising zincstannate, which is amorphous or substantially amorphous as deposited,may have a metal content of from about 40-60% Zn and from about 40-60%Sn (wt. %). In certain example embodiments, the coating may furthercomprise a layer comprising silicon nitride located over at least theamorphous or substantially amorphous layer comprising zinc stannate.

The coated article of any of the preceding seventeen paragraphs may bethermally tempered.

The coated article of any of the preceding eighteen paragraphs mayfurther comprise a metallic or substantially metallic absorber layerlocated between the glass substrate and the first IR reflecting layer.The absorber layer may be sandwiched between and contacting first andsecond layers comprising silicon nitride. The absorber layer maycomprise Ni and Cr (e.g., NiCr, NiCrMo), or any other suitable materialsuch as NbZr. The dielectric layer comprising at least one of (a), (b),and (c) may be located between at least the absorber layer and the firstcrystalline or substantially crystalline layer comprising zinc oxide.

In the coated article of any of the preceding nineteen paragraphs, theat least one dielectric layer comprising the oxide of zirconium maycomprise from 0-20% nitrogen, more preferably from 0-10% nitrogen, andmost preferably from 0-5% nitrogen (atomic %).

In the coated article of any of the preceding twenty paragraphs, theabsorber film may further comprises a layer comprising an oxide of Niand/or Cr located over and directly contacting the layer comprisingsilver of the absorber film.

In the coated article of any of the preceding twenty-one paragraphs, theabsorber film may be located over the first IR reflecting layer, so thatthe first IR reflecting layer is located between at least the absorberfilm and the glass substrate.

In the coated article of any of the preceding twenty-two paragraphs, theratio of the physical thickness of the first IR reflecting layercomprising silver to the physical thickness of the layer comprisingsilver of the absorber film may be at least 8:1, more preferably atleast 10:1, and even more preferably at least 15:1.

In the coated article of any of the preceding twenty-three paragraphs,the layer comprising silver of the absorber film may be less than 30 Åthick, more preferably less than 20 Å thick, and even more preferablyless than 15 Å thick.

In the coated article of any of the preceding twenty-four paragraphs,the coated article need not be thermally tempered.

In the coated article of any of the preceding twenty-five paragraphs,the at least one dielectric layer having monoclinic phase and comprisingthe oxide of zirconium may include two such layers comprising zirconiumoxide and may be located both: (1) between at least the glass substrateand the first crystalline or substantially crystalline layer comprisingzinc oxide doped with from about 1-30% Sn (wt. %), and (2) between atleast the first IR reflecting layer comprising silver and the absorberfilm.

In the coated article of any of the preceding twenty-six paragraphs, theat least one dielectric layer having monoclinic phase may comprise from0-5% nitrogen (atomic %).

In the coated article of any of the preceding twenty-seven paragraphs,the at least one dielectric layer having monoclinic phase may comprisean oxide of zirconium (e.g., ZrO₂), and may optionally further includeSi.

In the coated article of any of the preceding twenty-seven paragraphs,the at least one dielectric layer having monoclinic phase may consistessentially of an oxide of zirconium.

In the coated article of any of the preceding twenty-eight paragraphs,the at least one dielectric layer having monoclinic phase may beconfigured to realize a density change of at least 0.25 g/cm³ upon saidreference heat treatment, more preferably to realize a density change ofat least 0.30 g/cm³ upon said reference heat treatment, and mostpreferably to realize a density change of at least 0.35 g/cm³ upon saidreference heat treatment.

In the coated article of any of the preceding twenty-nine paragraphs,the at least one dielectric layer having monoclinic phase may comprisean oxide of zirconium, and may have a metal content of at least 80% Zr.

In the coated article of any of the preceding thirty paragraphs, the atleast one dielectric layer having monoclinic phase may comprise an oxideof zirconium and/or may have a thickness of from 40-250 Å, morepreferably from 40-170 Å, and most preferably from 80-140 Å.

In the coated article of any of the preceding thirty-one paragraphs, thecoated article may be configured to have, measured monolithically, twoor three of: (i) a transmissive ΔE* value of no greater than 3.0 upon areference heat treatment for 12 minutes at a temperature of about 650degrees C., (ii) a glass side reflective ΔE* value of no greater than1.5 upon the reference heat treatment for 12 minutes at a temperature ofabout 650 degrees C., and (iii) a film side reflective ΔE* value of nogreater than 1.5 upon the reference heat treatment for 12 minutes at atemperature of about 650 degrees C.

The coated article of any of the preceding thirty-two paragraphs may beprovided as a monolithic window, or in an IG window unit coupled toanother glass substrate.

In to coated article of any of the preceding thirty-three paragraphs,the at least one dielectric layer comprising monoclinic phase mayfurther comprise tetragonal phase before and/or after a reference heattreatment.

In an example embodiment, there is provided a method of making a coatedarticle including a coating on a glass substrate, the method comprising:sputter-depositing a layer comprising zinc on the glass substrate;sputter-depositing a first infrared (IR) reflecting layer comprisingsilver on the glass substrate over and contacting the layer comprisingzinc oxide; sputter-depositing at least one dielectric layer (e.g.,oxide of zirconium, such as ZrO₂) having monoclinic phase on the glasssubstrate, wherein the dielectric layer having monoclinic phasecomprises an oxide of zirconium (and which may further include otherelement(s) such as Si); wherein the at least one dielectric layer havingmonoclinic phase and comprising the oxide of zirconium is located: (1)between at least the glass substrate and the layer comprising zincoxide, and/or (2) between at least the first IR reflecting layercomprising silver and a second IR reflecting layer comprising silver ofthe coating; and wherein the coated article is configured to have,measured monolithically, at least two of: (i) a transmissive ΔE* valueof no greater than 3.0 upon a reference heat treatment for 12 minutes ata temperature of about 650 degrees C., (ii) a glass side reflective ΔE*value of no greater than 3.0 upon the reference heat treatment for 12minutes at a temperature of about 650 degrees C., and (iii) a film sidereflective ΔE* value of no greater than 3.5 upon the reference heattreatment for 12 minutes at a temperature of about 650 degrees C. T

In the method of the immediately preceding paragraph, saidsputter-depositing at least one dielectric layer having monoclinic phaseon the glass substrate may use an oxygen gas flow of at least 6 ml/kW,more preferably an oxygen gas flow of at least 8 or 10 ml/kW.

In the method of any of the preceding two paragraphs, the at least onedielectric layer having monoclinic phase may comprise ZrO₂, and mayfurther include Si.

In the method of any of the preceding three paragraphs, the coatedarticle may be configured to have, measured monolithically, at least twoor all three of: (i) a transmissive ΔE* value of no greater than 3.0upon a reference heat treatment for 12 minutes at a temperature of about650 degrees C., (ii) a glass side reflective ΔE* value of no greaterthan 1.5 upon the reference heat treatment for 12 minutes at atemperature of about 650 degrees C., and (iii) a film side reflectiveΔE* value of no greater than 1.5 upon the reference heat treatment for12 minutes at a temperature of about 650 degrees C.

The method of any of the preceding four paragraphs may further compriseheat treating the coated article via said reference heat treatment sothat the at least one dielectric layer having monoclinic phase realizesa density change of at least 0.25 g/cm³ upon said reference heattreatment, more preferably at least 0.30 g/cm³, and most preferably ofat least 0.35 g/cm³.

In the method of any of the preceding five paragraphs, saidsputter-depositing of the at least one dielectric layer havingmonoclinic phase on the glass substrate may use a metal target, or aceramic target.

In the method of any of the preceding six paragraphs, said at least onedielectric layer comprising monoclinic phase may further comprisetetragonal phase before and/or after said reference heat treatment.

In the method of any of the preceding seven paragraphs, the at least onedielectric layer comprising monoclinic phase may be configured to have amonoclinic peak thereof reduce upon said reference heat treatment.

Once given the above disclosure many other features, modifications andimprovements will become apparent to the skilled artisan. Such otherfeatures, modifications and improvements are therefore considered to bea part of this invention, the scope of which is to be determined by thefollowing claims:

1-60. (canceled)
 61. A coated article including a coating on a glasssubstrate, wherein the coating comprises: a first crystalline orsubstantially crystalline layer comprising zinc oxide, located on theglass substrate; a first infrared (IR) reflecting layer comprisingsilver located on the glass substrate and directly over and contactingthe first crystalline or substantially crystalline layer comprising zincoxide; at least one dielectric layer having monoclinic phase andcomprising an oxide of zirconium; wherein the at least one dielectriclayer having monoclinic phase and comprising the oxide of zirconium islocated: (1) between at least the glass substrate and the firstcrystalline or substantially crystalline layer comprising zinc oxide,and/or (2) between at least the first IR reflecting layer comprisingsilver and a second IR reflecting layer comprising silver of thecoating; wherein the coated article is configured to have, measuredmonolithically, at least two of: (i) a transmissive ΔE* value of nogreater than 3.0 upon a reference heat treatment for 12 minutes at atemperature of about 650 degrees C., (ii) a glass side reflective ΔE*value of no greater than 3.0 upon the reference heat treatment for 12minutes at a temperature of about 650 degrees C., and (iii) a film sidereflective ΔE* value of no greater than 3.5 upon the reference heattreatment for 12 minutes at a temperature of about 650 degrees C. 62.The coated article of claim 61, wherein the coating further comprises anabsorber film that comprises a layer comprising an oxide of Ni and/or Crlocated over and directly contacting a layer comprising silver of theabsorber film.
 63. The coated article of claim 62, wherein the absorberfilm is located over the first IR reflecting layer, so that the first IRreflecting layer is located between at least the absorber film and theglass substrate.
 64. The coated article of claim 62, wherein a ratio ofa physical thickness of the first IR reflecting layer comprising silverto a physical thickness of the layer comprising silver of the absorberfilm is at least 8:1.
 65. The coated article of claim 62, wherein thelayer comprising silver of the absorber film is less than 60 Å thick.66. The coated article of claim 62, wherein the layer comprising silverof the absorber film is less than 30 Å thick.
 67. The coated article ofclaim 61, wherein the coated article is configured to have, measuredmonolithically, all three of: (i) a transmissive ΔE* value of no greaterthan 3.0 upon a reference heat treatment for 12 minutes at a temperatureof about 650 degrees C., (ii) a glass side reflective ΔE* value of nogreater than 3.0 upon the reference heat treatment for 12 minutes at atemperature of about 650 degrees C., and (iii) a film side reflectiveΔE* value of no greater than 3.5 upon the reference heat treatment for12 minutes at a temperature of about 650 degrees C.
 68. The coatedarticle of claim 61, wherein the at least one dielectric layercomprising monoclinic phase is located at least between at least theglass substrate and the first crystalline or substantially crystallinelayer comprising zinc oxide.
 69. The coated article of claim 61, whereinthe at least one dielectric layer comprising monoclinic phase is locatedat least between at least the first IR reflecting layer comprisingsilver and the second IR reflecting layer comprising silver of thecoating.
 70. The coated article of claim 61, wherein said coatedarticle, measured monolithically, has a visible transmission of at least40%.
 71. The coated article of claim 61, wherein the coating asdeposited further comprises a first amorphous or substantially amorphouslayer comprising zinc stannate located on the glass substrate over atleast the first IR reflecting layer comprising silver.
 72. The coatedarticle of claim 61, wherein the at least one dielectric layercomprising monoclinic phase comprises from 0-5% nitrogen (atomic %). 73.The coated article of claim 61, wherein the at least one dielectriclayer comprising monoclinic phase comprises ZrO₂.
 74. The coated articleof claim 61, wherein the at least one dielectric layer comprisingmonoclinic phase consists essentially of the oxide of zirconium.
 75. Thecoated article of claim 61, wherein the at least one dielectric layercomprising monoclinic phase is configured to realize a density change ofat least 0.25 g/cm³ upon heat treatment.
 76. The coated article of claim61, wherein the at least one dielectric layer comprising monoclinicphase comprises an oxide of zirconium, and has a metal content of atleast 80% Zr.
 77. The coated article of claim 61, wherein the at leastone dielectric layer comprising monoclinic phase and comprising theoxide of zirconium has a thickness of from 40-170 Å.
 78. The coatedarticle of claim 61, wherein the at least one dielectric layercomprising monoclinic phase and comprising the oxide of zirconium,further comprises Si.
 79. The coated article of claim 61, wherein nosilicon nitride based layer is located directly under and contacting thelayer comprising zinc oxide.